With the gradual transformation of traditional agriculture into modern agriculture, agricultural mechanization has played a very important role in the contribution rate of the whole people’s economy in Jiangxi Province. Because of the wide application of Cobb-Douglas (C-D) production function in western economics, many scholars have used this method in practice in recent years. By establishing the C-D production function model, the agricultural mechanization data of Jiangxi Province from 2005 to 2019 are analyzed, and the factors such as agricultural output value, agricultural mechanization input, agricultural material consumption, labor input and land input play a key role in the economic growth of agricultural mechanization development.