Farmers in China generally have unreasonable fertilization behavior. Agricultural extension services are not only related to popularizing scientific fertilization technology but also affect farmers’ subsequent technology use behavior to a great extent, which is a critical factor in promoting farmers’ scientific fertilization. This study aims to clarify whether there are differences in the impact of agricultural extension services provided by different organizations on farmers’ fertilization behavior, and to explore the feasible path of agricultural extension services to promote farmers’ scientific fertilization. This study used the survey data of 1262 farmers in the main rice-producing areas of Hubei Province to empirically analyze the impact and mechanism of agricultural extension services on farmers’ scientific fertilization behavior. The study finds that agricultural extension services have a significant positive impact on farmers’ scientific fertilization behavior. Moreover, the impact of different agricultural extension service providers on farmers’ scientific fertilization behavior varies. Specifically, the public sector and farmers’ organizations have a more significant impact on farmers’ scientific fertilization behavior than the private sector. The public and private sectors promote farmers’ scientific fertilization behavior by increasing their value perception. These findings help clarify the influencing factors of farmers’ fertilization behavior, clarify the path of agricultural technology extension services, and provide practical policy guidance for developing countries to reduce fertilizer effectively.