["Asian-Pacific Economic Literature, EarlyView. ", "\nABSTRACT\nActive promotion of biopesticides represents a critical pathway towards achieving sustainable agricultural development in China. In the context of ongoing agricultural digitization, digital extension has emerged as a transformative approach for disseminating agricultural technologies. Based on survey data collected from 793 farmers in China, this study employed a propensity score matching (PSM) method to analyse the impact of digital extension on farmers' biopesticide adoption behaviour. Furthermore, we examined the heterogeneous effects of different digital extension modes. The findings reveal that digital extension increased the likelihood of biopesticide use by farmers by approximately 2.6%–4.3%. Among the various digital modes—graphic‐based extension, live broadcasting and short videos—the short video format proved most effective in promoting biopesticide application. Additionally, digital extension and traditional technical training were found to exhibit a complementary effect, enhancing each other's influence. The positive impact of digital extension was more pronounced among young and middle‐aged farmers, while an observable digital divide limited its effectiveness among older farmers. These results underscore the significance of designing targeted, mode‐aware digital promotion strategies to encourage environmentally sustainable farming practices. They also highlight the need for complementary integration of online and offline agricultural extension services to maximise outreach and efficacy.\n"]