The paper provides an improved analytic hierarchy process which is on the basis of the real coding accelerating genetic algorithm(RAGA-AHP).It can identify the improtance ranking value of different factors from differernt hierarchy at the same time,and change the conformance test that estimate matrix to an optimization problem for nonlinear system.RAGA-AHP is intuitive,effective and easy to use.Its calculating accuracy is higher than other methods currently.It has a wide range of applicability for all kinds of practical questions.The paper provides an empirical study on China dairy industy with this method,and points out the preferential relation in the problem of China dairy industry.