There are few studies on the correlation between fertilizer reduction and pesticide reduction in agricultural production. However, exploring the synergy of fertilizer and pesticide reduction (SFPR) is crucial to the comprehensive realization of sustainable agriculture. This study reveals the spatialtemporal evolution patterns of the SFPR in China using the Thiel index and elasticity coefficient methods. The influencing factors of SFPR are empirically based on Synergy Theory. The results show that the proportion of China’s fertilizer reduction is 12.43% and pesticide reduction is 27.32% from 2014 to 2020. That is, the performance of pesticide reduction is more significant in China. And there is a synergistic and positive correlation between fertilizer and pesticide reduction in the provinces of China. The results of the panel data regression model show that the SFPR relies significantly on government policy, financial support, agricultural planting structure, per capita GDP, and agricultural output value. Therefore, this study recommends further strengthening the awareness of responsibility for fertilizer and pesticide reduction at the provincial government and promoting the projects of fertilizer and pesticide reduction via a systematic approach.