Agricultural socialized services (ASS) play an important role in connecting smallholders with modern agriculture and in strengthening agricultural economic resilience (AER). Using panel data from 30 Chinese provinces for 2011–2022, this study applies two-way fixed-effects, mediation, and threshold models to examine the effect of ASS on AER and the associated mechanisms. The results show that: (1) ASS significantly enhances AER, and this finding remains robust after excluding municipalities and the COVID-19 period; (2) the positive effect of ASS is more pronounced in non-major grain-producing regions than in major grain-producing regions; (3) ASS strengthens AER by reducing agricultural product import dependence and expanding agricultural operation scale; and (4) agricultural industrial restructuring exhibits a threshold effect, with the effect of ASS becoming positive when the restructuring coefficient exceeds 0.0057. Based on these findings, this study recommends improving the agricultural socialized service system, strengthening domestic agricultural supply capacity, diversifying supply channels, promoting land transfer and moderate-scale operations, and aligning service policies with regional industrial restructuring.