Although experimental biochemical & biophysical measurements have been developed rapidly, understanding and designing complex biomolecular systems is still quite challenging. Computer simulation based on captured biopolymer structures (by X-ray, NMR etc.) can be an essential complementary technique to catalyze our exploration of microscopic world. Due to the complexity of biological systems in both length scale and time scale, biomolecular simulation need to be both functional and efficient; facing this challenge, my research interest targets the development and application of state-of-art multi-spectrum atomistic simulation techniques including QM/MM calculation, free energy simulation, conformation path simulation, motion analysis etc., to understand the hidden nature of complex biological phenomena. Specifically, my research program includes three directions: 1) first principle based protein and ligand design, 2) simulation study of multi-timescale biochemical & biophysical events, and 3) development of simulation techniques to describe complex systems and enhance efficiency of biomolecular simulations.