Based on situational theory of culture, the paper discusses the mechanisms of high performance work system(HPWS) on knowledge sharing. The model of these varibles is tested by analyzing the datas collected from 1749 knowledge staffs in the Northeast in China.The results suggest that HPWS has a significant positive impact on knowledge sharing,and organizational culture moderates this relationship effectively. The more supports for knowledge sharing in the culture, the more significant positive relationship of HPWS and knowledge sharing.