Abstract: The paper aims at the insufficient socialized public service of agricultural machinery for small-scale family management in agriculture. We discussed main factors affecting the purchase demand of agricultural machinery service by grain farmers based on investigations in Jiangxi and Guangdong. The results showed that: the level of county economic development and transportation condition of natural villages had significantly positive impact on the demand of the socialized service of agricultural machinery, occupation and the actual land area had significantly negative impact, while farmer’s age, educational level, family labor force, the proportion of agricultural income to the total income, land fragmentation, farmers’assessment on subsidies for purchasing agricultural machinery had no significant impact. Therefore, accelerating the development of local economy, improving transportation condition and enhancing agricultural subsidy policy are beneficial to improving the demand level of socialized service of agricultural machinery of farmers and upgrading agricultural mechanization level.