Abstract: The essence of agricultural machinery socialized services is division of labor and specialization, and optimization of factor allocation, which in turn affects the efficiency of agricultural grain production. Therefore, exploring the specific impact of agricultural machinery socialized services on agricultural grain production efficiency is of great significance for achieving agricultural modernization and promoting rural revitalization in China. Based on the mixed crosssectional data from the CLDS database in 2014 and 2016, this study empirically examines the impact of agricultural machinery socialized services on agricultural grain production efficiency using the stochastic frontier analysis （SFA） method and mediation effect models. The results indicate that: agricultural machinery socialized services can effectively improve the efficiency of agricultural grain production. Both agricultural policies and land management scale influence the effectiveness of agricultural machinery socialized services. Three factors allocation strategies play significant mediating roles. The socialized services of agricultural machinery improve the efficiency of agricultural grain production by increasing the degree of parttime framing, increasing shortterm agricultural input, and reducing longterm investment. Under certain conditions, however, the services may restrict the land transfer among farmers, thereby reducing their agricultural grain production efficiency.

Key words: agricultural machinery socialized services, factor allocation, grain production efficiency, stochastic frontier analysis, mediation effect

摘要： 农机社会化服务本质上是分工与专业化，并优化要素配置，而要素优化配置又会影响农业粮食生产效率，因此，探究农机社会化服务对农业粮食生产效率的具体影响对于实现我国农业现代化，助推乡村振兴具有重要意义。基于CLDS数据库中2014年、2016年的混合截面数据，运用随机前沿一步法以及中介效应模型实证研究农机社会化服务对农业粮食生产效率的影响。研究结果表明：农机社会化服务能有效提高农业粮食生产效率。农业政策与土地经营规模均会影响农机社会化服务作用效果。3种要素配置手段均发挥显著中介作用。农机社会化服务通过提高兼业化程度、提高农业短期投入、降低长期投资，以提高农业粮食生产效率，但在一定条件下会限制农户土地流转，从而降低其农业粮食生产效率。

关键词: 农机社会化服务, 要素配置, 粮食生产效率, 随机前沿一步法, 中介效应