This study investigates the impact of agricultural machinery adoption modes—service outsourcing (SO) and self-purchase (SP)—on food productivity in China, using data from 795 grain farmers in the North China Plain. The results show that SP improves technical efficiency but reduces input efficiency of agricultural machinery compared to SO. The effect of adoption mode on food productivity is asymmetric among different types of farmers. Large-scale and professional farmers benefit more from SP, while small-scale and part-time farmers benefit more from SO. The study highlights the challenges of AMS suppliers' opportunistic behavior and labor supervision issues, which reduce the quality of agricultural machinery operations. The findings suggest that the Chinese government should adjust agricultural machinery subsidy policies to reduce transaction costs and address the loss of technical efficiency caused by opportunistic behavior. The study also emphasizes the need for skill training for agricultural machinery operators to improve operational quality and reduce transaction costs. The results indicate that SP enhances technical efficiency but may reduce input efficiency, while SO improves input efficiency but may reduce technical efficiency. The study provides insights into the complex relationship between agricultural machinery adoption modes and food productivity, highlighting the importance of considering the characteristics of different farmer groups when designing agricultural policies.This study investigates the impact of agricultural machinery adoption modes—service outsourcing (SO) and self-purchase (SP)—on food productivity in China, using data from 795 grain farmers in the North China Plain. The results show that SP improves technical efficiency but reduces input efficiency of agricultural machinery compared to SO. The effect of adoption mode on food productivity is asymmetric among different types of farmers. Large-scale and professional farmers benefit more from SP, while small-scale and part-time farmers benefit more from SO. The study highlights the challenges of AMS suppliers' opportunistic behavior and labor supervision issues, which reduce the quality of agricultural machinery operations. The findings suggest that the Chinese government should adjust agricultural machinery subsidy policies to reduce transaction costs and address the loss of technical efficiency caused by opportunistic behavior. The study also emphasizes the need for skill training for agricultural machinery operators to improve operational quality and reduce transaction costs. The results indicate that SP enhances technical efficiency but may reduce input efficiency, while SO improves input efficiency but may reduce technical efficiency. The study provides insights into the complex relationship between agricultural machinery adoption modes and food productivity, highlighting the importance of considering the characteristics of different farmer groups when designing agricultural policies.