Abstract: This paper takes 251 hi-tech SMEs in Shenzhen Stock Exchange from 2011 to 2018 as samples, applies negative binomial regression to study the impact of government subsidies on innovation of hi-tech SMEs and the moderating effect of financing constraints, also analyzes the impact of government subsidies on innovation of enterprises in different life cycles and the moderating effect of financing constraints. The results show that government subsidies can promote innovation of hi-tech SMEs, but the financing constraints of hi-tech SMEs will weaken the incentive effect of government subsidies on innovation of hi-tech SMEs. From different life cycle stage, no matter in the growth and maturation, government subsidies play a positive role in promoting innovation of hi-tech SMEs, financing constraints play a negative regulatory role on government subsidies and innovation, but have no significant for government subsidies relationship with innovation of hi-tech SMEs in mature stage. Finally, this paper puts forward feasible suggestions to promote innovation of hi-tech SMEs from the perspectives of financing constraints and life cycle.