During the development of scientific and technological innovation, the importance of Government Purchasing Public Services (GPPS) in the field of science and technology (S&T) has become increasingly prominent. To investigate the relationship between Government Purchasing Science and Technology Public Services (GPSTPS) and regional S&T innovation ability, this paper first constructs a PMC index model to estimate GPSTPS objectively. Then, the spatial econometric model is adopted to explore the impact of GPSTPS policy on the regional S&T innovation ability based on the provincial panel data from 2008 to 2017 in China. Results show that: (1) Regional S&T innovation ability has a significant spatial positive correlation in geographical space from 2008 to 2017. (2) From the overall perspective, the GPSTPS policy does not play a role in improving the regional S&T innovation ability. (3) From the perspective of subregions, there are differences in the impact of GPSTPS on the regional S&T innovation ability between the eastern, central and western regions of China. (4) From the perspective of spatial spillover effect, the policy of GPSTPS has a positive spatial spillover effect on the improvement of regional S&T innovation ability in the eastern region, while the effect is not obvious in central and western regions.