曾任南京大學(xué)數(shù)學(xué)系主任、教授、博士生導(dǎo)師。

1983年畢業(yè)于徐州師范學(xué)院﹔

1986年獲南京大學(xué)理學(xué)碩士學(xué)位﹔

1989年獲北京大學(xué)理學(xué)博士學(xué)位后到南京大學(xué)任教。

1994年2月8日訪問(wèn)瑞士蘇黎世高工（ETH）數(shù)學(xué)研究所﹔

1995年至1997年受德國(guó)洪堡基金會(huì)資助在科隆大學(xué)和慕尼黑工業(yè)大學(xué)做合作研究﹔

1998年2月至8月在羅馬第三大學(xué)做訪問(wèn)教授；

1998年成為國(guó)家非線性科學(xué)攀登項(xiàng)目組正式成員﹔

1999年獲得國(guó)家杰出青年基金﹔

2000年成為國(guó)家重點(diǎn)基礎(chǔ)研究發(fā)展規(guī)劃項(xiàng)目組（非線性科學(xué)）成員；

2016年9月，擔(dān)任南開(kāi)大學(xué)陳省身數(shù)學(xué)研究所教授、博士生導(dǎo)師。

2017年12月，當(dāng)選中國(guó)民主同盟第十二屆中央委員會(huì)委員。

主要是動(dòng)力系統(tǒng)﹐特別是Hamilton動(dòng)力系統(tǒng)。研究成果主要集中在KAM理論及其在常微分方程和偏微分方程中的應(yīng)用方面﹔對(duì)低維環(huán)面的KAM理論做出了重要發(fā)展﹐在第一Melnikov非共振條件下得到了不變環(huán)面的存在性﹐并用于研究了國(guó)際上非�；钴S的Hamilton偏微分方程的擬周期解問(wèn)題﹔研究成果否定了1994年菲爾茨獎(jiǎng)獲得者Bourgain認(rèn)為KAM理論不能用于重法頻率的看法﹔解決了KAM理論創(chuàng)始人之一Moser關(guān)於擺方程Lagrange穩(wěn)定性的一個(gè)公開(kāi)問(wèn)題﹔受到了國(guó)際同行的重視和好評(píng)。

2.KAM theory for lower dimensional tori of nearly integrable Hamiltonian systems, Progress in Nonlinear Analysis, edited by K-C. Chang and Y. Long, World Scientific, 2000, 409-423.

3.KAM tori for 1D nonlinear wave equations with periodic boundary condition, Communications in Mathematical Physics., Vol. 211(2), 497-525, 2000(with l, Chierchia).

4.Perturbations of lower dimensional tori for Hamiltonian systems, Journal Of Differential Equations, Vol. 152, 1-29, 1999.

5.A KAM theorem for hyperbolic type degenerate lower dimensional tori in Hamiltonian systems, Communications in Mathematical Physics, Vol. 192. 145-168, 1998.

Almost reducibility and non-perturbative reducibility of quasi-periodic linear systems. Invent. Math. 190 (2012), no. 1, 209u2013260. Article; E-Journal.　　X. Hou and J. You

An infinite dimensional KAM theorem and its application to the two dimensional cubic Schrödinger equation. Adv. Math. 226 (2011), no. 6, 5361u20135402. Article; E-Journal.　　J. Geng, X. Xu and J. You

Persistence of the non-twist torus in nearly integrable Hamiltonian systems. Proc. Amer. Math. Soc. 138 (2010), no. 7, 2385u20132395.Article; E-Journal.　　J. Xu and J. You

Local rigidity of reducibility of analytic quasi-periodic cocycles on U(n). Discrete Contin. Dyn. Syst. 24 (2009), no. 2, 441u2013454.Article; E-Journal.　　X. Hou and J. You

Corrigendum for the paper: "Two-dimensional invariant tori in the neighborhood of an elliptic equilibrium of Hamiltonian systems" in Acta Mathematica Sinica, English Series August 2009, Volume 25, Issue 8, pp 1363-1378. Article　　H. Lu and J. You

Two-dimensional invariant tori in the neighborhood of an elliptic equilibrium of Hamiltonian systems. Acta Mathematica Sinica, English Series August 2009, Volume 25, Issue 8, pp 1363-1378. Article; E-Journal.　　H. Lu and J. You

Full measure reducibility for generic one-parameter family of quasi-periodic linear systems. J. Dynam. Differential Equations 20 (2008), no. 4, 831u2013866. Article; E-Journal.　　H. He and J. You

The rigidity of reducibility of cocycles on SO(N ,R). Nonlinearity 21 (2008),no. 10, 2317u20132330. Article; E-Journal. 　　X. Hou and J. You

Diophantine vectors in analytic submanifolds of Euclidean spaces. Sci. China Ser. A. 50 (2007), no. 9, 1334u20131338. Article; E-Journal.　　R. Cao and J. You

Corrigendum for the paper: "Invariant tori for nearly integrable Hamiltonian systems with degeneracy" [Math. Z. 226 (1997), no. 3, 375u2013387] by Xu, You, and Q. Qiu. Math. Z. 257 (2007), no. 4, 939. Article; E-Journal.　　J. Xu and J. You

Gevrey-smoothness of invariant tori for analytic nearly integrable Hamiltonian systems under Rüssmann’s non-degeneracy condition. J. Differential Equations 235 (2007), no. 2, 609u2013622. Article; E-Journal.　　J. Xu and J. You

KAM Tori for Higher Dimensional Beam Equation with Constant Potentials, Nonlinearity 19 (2006), no. 10, 2405u20132423. Article; E-Journal.　　J. Geng and J. You

The Existence of Integrable Invariant Manifolds of Hamiltonian Partial Differential Equations, Discrete and Continuous Dynamical Systems 16 (2006), no. 1, 227u2013234. Article; E-Journal.　　R.Cao and J. You

An Improved Result for Positive Measure Reducibility of Quasi- periodic Linear Systems, Acta Mathematica Sinica (English series) 22 (1), 2006, 77-86. Article; E-Journal.　　H. He and J. You

A KAM Theorem for Partial Differential Equations in Higher Dimensional Space, Communications in Mathematical Physics, Vol.262(2), 2006, 343-372. Article; E-Journal.　　J.Geng and J.You

Umbilical Torus Bifurcations in Hamiltonian Systems, J. Differential Equations, Vol. 222(1), 2006, 233-262. Article; E-Journal.　　H. Broer, H. Hanssmann and J. You

A simple proof of diffusion approximations for LBFS re-entrant lines, Oper. Res. Lett., 34(2006), no. 2, 199u2013204. Article; E-Journal.　　J. Yang, J.G. Dai, J. You and H. Zhang

Quasi-Periodic Solutions for 1D Schrödinger Equations with Higher Order Nonlinearity, SIAM J. Mathematical Analysis, 36(2005), 1965-1990. Article; E-Journal.　　Z. Liang and J. You

Bifurcations of Normally Parabolic Tori in Hamiltonian Systems, Nonlinearity, 18 (2005) 1735-1769. Article; E-Journal.　　H. Broer, H. Hanssmann and J. You

A KAM Theorem for One Dimensional Schrödinger Equation with Periodic Boundary Conditions, J. Differential Equations, 209, 2005, 1-56. Article; E-Journal.　　J. Geng and J. You

KAM tori of Hamiltonian perturbations of 1D linear beam equations, J.Math.Anal.Appl., 277, 2003, 104-121. Article; E-Journal.　　J. Geng and J. You

A Symplectic Map and its Application to the Persistence of Lower Dimensional InvariantTori, Science in China, 45(5), 2002,598-603. Article; E-Journal.

曾獲得國(guó)家杰出青年基金、香港求是科技基金會(huì)杰出青年學(xué)者獎(jiǎng)、中國(guó)高校科技進(jìn)步獎(jiǎng)一等（排名第二）、第六屆江蘇省青年科技獎(jiǎng)、國(guó)家自然科學(xué)二等獎(jiǎng)（排名第三）。