His research interests include physical and logic synthesis for high-performance low-power VLSI circuits, design and optimization of high-speed VLSI interconnects, and design, synthesis, and compilation for programmable/reconfigurable architectures. He has published over 180 research papers and led over 30 research projects in these areas. He served as the General Chair of the 1993 ACM/SIGDA Physical Design Workshop, the Program Chair and General Chair of the 1997 and 1998 Int'l Symp. on FPGAs, respectively, Program Co-Chair of the 1999 Int'l Symp. on Low-Power Electronics and Designs, Program Co-Chair of ASPDAC'2003, and on program committees of many major conferences, including DAC, ICCAD, and ISCAS. He is an Associate Editor of IEEE Trans. on VLSI Systems and ACM Trans. on Design Automation of Electronic Systems.
Dr. Cong received the Best Graduate Award from the Peking University in 1985, and the Ross J. Martin Award for Excellence in Research from the University of Illinois at Urbana-Champaign in 1989. He received the NSF Young Investigator Award in 1993, the Northrop Outstanding Junior Faculty Research Award from UCLA in 1993, the IEEE Trans. on CAD Best Paper Award in 1995 from IEEE CAS Society, and the ACM and SIGDA Meritorious Service Award in 1998. He received an SRC Inventor Recognition Award in 2000 and the SRC Technical Excellence Award for Year 2000. He was elected to an IEEE Fellow in 2000 and an ACM Fellow in 2008. With over 200 publications  in the field of CAD he is considered one of the top people in his field.
In the 1990s, Jason Cong proposed the interconnect centric design flow, emphasizing delay caused by interconnect. This work soon became acknowledged by the industry. Many of his students, including Lei He, Cheng-Kok Koh, David Pan, became renowned professors in universities.
In 2003, his work 'optimality study of placement algorithms' shocked both academia and industry. It was found that wirelength driven placement - a problem that had been studied for 30 years, widely regarded as well-studied, was far from solved successfully. Jason made some artificial benchmarks with known optima, and found that existing tools and algorithms are far from optimal. This study led to extensive study on wirelength driven placement in the subsequent years which included ISPD, an international conference focusing on VLSI physical design, holding a placement contests for 3 successive years.