Abstract: Agricultural input dealers are deeply rooted in rural society and serve as a crucial bridge connecting small-scale farmers with modern agriculture, profoundly influencing the behavioral decisions of tea farmers. This paper divides tea farmers’ adoption of green prevention and control technologies into two dimensions: adoption breadth and adoption depth. Based on the perspective of social capital, a theoretical framework is developed to analyze the impact of agricultural input dealers on the adoption of green prevention and control technologies by tea farmers. Using survey data from tea farmers in key tea-producing regions of Shaanxi, Anhui, and Sichuan provinces, ordered Probit and Double-Hurdle models are applied to empirically investigate the influence of agricultural input dealers on tea farmers’ adoption of green prevention and control technologies. Furthermore, the moderating role of government regulation in this process is examined. The results show that: 1) regarding adoption breadth, agricultural input networks, norms, and participation significantly promote tea farmers to adopt a wider range of green prevention and control technologies, while the effect of trust in agricultural input dealers is not significant; 2) regarding adoption depth, agricultural input networks significantly increase the adoption depth of all three types of prevention and control technologies; trust in input dealers positively affects the adoption depth of biological control but has no significant impact on other technologies; norms promote the adoption depth of biological and chemical control technologies; participation mainly affects the adoption depth of physical control; 3) government incentive-based, restrictive, and guidance-based regulations play significant moderating roles in the impact of agricultural input dealers on tea farmers’ adoption of green prevention and control technologies. Based on the findings, this paper recommends strengthening the interaction between agricultural input dealers and tea farmers, optimizing financial support for green prevention and control technologies, enhancing training and promotion efforts, and reinforcing government supervision and support.