According to China’s current situation in agricultural informatization development and the functions of the Ministry of Agriculture, and on a basis of the connotation of “agricultural informatization”, this paper initially establishes a quantitative agricultural informatization evaluation index system which could reflect the actual level of every province’s agricultural informatization. The index system consists of 12 indexes selected from 3 aspects, which are agricultural informatization foundational support level, agricultural production and operation informatization level, as well as agricultural management and service informatization level. At the same time, on the basis of summarizing the accomplishments of other researchers, a set of calculation methods/algorithms are proposed in the paper to evaluate the agricultural informatization level.