Sustainable agricultural development has been the policy priority for countries with limited natural resources. New farmers’ emergence and growth have not only helped to address the labor crisis in agriculture to some extent, but they have also improved, integrated, and expanded the agricultural sectors. However, less attention has been paid to the performance of new farmers in adopting sustainable agricultural practices and the related spatial effects. Also, few studies have combined the composite adoption intensity of sustainable agricultural practices with the effects of various specific measures. Therefore, this study constructed the Tobit MLE spatial cross-section regression models to empirically study a sample of 174 farmers. We attempted to analyze the impact of the new farmers group on the diffusion of sustainable agricultural practices as well as farmers’ influence on various sorts of sustainable agricultural practices. The results show that new farmers greatly enhanced the adoption of sustainable agricultural practices, as evidenced by the fact that their adoption level was 69.9% greater than that of traditional farmers. However, they had statistically significant negative spillover effects on their neighboring farmers. For the composite adoption intensity of sustainable agricultural practices, there were also statistically significant negative spillover effects. Additionally, there were notable disparities among the factors influencing farmers’ decisions to adopt various types of sustainable agricultural practices and the spatial effects of those adoptions, particularly in the farm size, the number of plots, and the variety of marketing methods employed by farmers. Therefore, measures need to be proposed to address the barriers to the implementation and diffusion of various types of sustainable agricultural practices. This would increase farmers’ willingness to adopt sustainable agricultural practices and the effectiveness of their motivation to neighboring farmers.