Abstract: The existing studies that cultural distance influence cross-border knowledge spillover have a large number of conflicting conclusions. Many scholars have questioned understanding national cultural differences from a single perspective of cultural values. Thus, this study explains the effect of cultural distance on cross-border knowledge spillover by learning from the relevant theories of knowledge absorptive capacity, while introduce cultural tightness based on social norms, and then respectively discuss the interaction between the cultural tightness of knowledge absorbing country, the cultural tightness of knowledge diffusing country and their cultural distance. By conducting negative binomial regression analysis using panel data of cross-border patent citation among 17 countries in 1997-2006, it is found that cultural distance has a significant negative influence on cross-border knowledge spillover, and the cultural tightness of knowledge absorbing country plays a positive moderating role in this relationship. However, the cultural tightness of knowledge diffusing country doesn’t make significant moderating effect, but impacts cross-border knowledge spillover negatively. The study provides theoretical reference for managers making decisions about cross-border knowledge spillovers and promoting innovative knowledge exchange with other countries.