Abstract: The main characters of agricultural data are massive, complex, disperse and difficult to acquire. With the developing of modern agriculture, the massive non-relational and unstructured data appeared, data mining technology based on big data can extract valuable information from massive data, and contribute to research the potential relativity and rules of agriculture information. This paper analyzed the characters of agricultural data, and the status of data analysis and the superiority of big data technology, developed the agricultural big data mining system based on Hadoop, and studied the architecture, module designing and system realization.