Based on sample data from 4074 agricultural machinery households in 100 hilly counties across of China，this study examines the impact and mechanisms of farmland suitability for agricultural machinery operations （FSAM） on the supply behavior of agricultural machinery services by agricultural machinery households.The research finds that the level of FSAM can increase both the probability and the level of agricultural machinery service supply by agricultural machinery households.The positive impact on service supply level is significant in terms of both the number of service supply links and service supply area.Mechanism analysis reveals that the level of FSAM enhances the agricultural machinery service supply probability and number of agricultural machinery service supply links of agricultural machinery households by expanding the market size for agricultural machinery service, and increases the service supply area by improving the operational efficiency of agricultural machinery.Heterogeneity analysis indicates that the promotion effect of FSAM on the agricultural machinery service supply by young and middle-aged agricultural machinery households is greater than that on middle-aged households.The impact on the service supply level of elderly agricultural machinery and the number of service supply links for households with an operating scale of less than 50 mu is not significant.