Abstract: Two parts of analytic hierarchy process (AHP) were improved.One is that the parameters “x_min^jand x_maxj”of the original model(x_ij-x_min^j)/(x_max^j-x_min^j)are substituted by the parameter“x₀^j” of a new model(x_ij-x₀^j)/x₀^j,which is obtained from an experiment.The other change is that the linear formula “P(x_ij)=1+4×(x_ij-x_min^j)/(x_max^j-x_min^j)” is replaced by a parabola formula “P(x_ij)=(x_ij-x₀^j)/x₀^jn”. The comprehensive benefits of irrigation systems of wheat were evaluated with two models,and the results are different between two models.The results of the new model break away from the relative comparison of pure mathematics in the original model and can reflect the true value both of the individual and comprehensive benefit more accurately.So the results of the new model are more beneficial and practical to production.