Based on the spatial Durbin model, this paper explored postgraduate education's influence and spatial effects on technological innovation. Using China's provincial panel data from 2004 to 2018, study results revealed that distribution of postgraduates in China showed spatial autocorrelation and non-equilibrium. Overall, postgraduate education positively impacted technological innovation. The study measured spatial spillover using three spatial weight matrices, finding that postgraduate education significantly promoted innovation in similar provinces. The spatial spillover effect in the economic matrix was stronger than that in the adjacent matrix. In economic and economic-geographical matrices, postgraduate education's spatial spillover effect was stronger than its direct effect. This paper can deepen understanding of characteristics and functions of postgraduate education in a rapidly developing economy.