Based on the assessment of Agricultural Informationalization level, this paper proposed a model for the Agricultural Informationalization benefit analysis whit the Cobb-Douglas production function, to reveal the connection between agri-information index and the agricultural output, and also we made an empirical analysis of Shandong province. It is proved that the Agricultural Informationalization and the farming population both have a direct and positive impact on the development of rural economy in Shandong Province, especially, the development of the Agricultural Informationalization level has a significant influence on the increase of the rural economy in Shandong province , while the impact brought by agricultural fixed asset investment remains limited. By 1% increase of Agricultural Informationalization level, the rural economy increases by 0.565%, which indicates that Agricultural Informationalization is quite beneficial for the development of Shandong’s agricultural economy.