Abstract: Primary task of sustainable development of modern agricultural economy in China is to efficiently utilize agricultural resources.Improving level of agricultural mechanization is one of the important ways to utilize agricultural resources efficiently and promote sustainable development of agricultural economy.Relationship between agricultural mechanization and sustainable development of agricultural economy was outlined.Development trend of agricultural mechanization and level of agricultural mechanization in developed countries were introduced.In order to promote sustainable development of agricultural economy，4 measures were put forward，including strengthening policy support，promoting highly specialized agricultural machinery research，building rural professional cooperative organizations，and accelerating construction of agricultural scale production.