Abstract: To solve the problems of the ordered propositions, an evidence theory model is given. But this model produces a combinational error because of computing precision. This problem is solved by presenting a new method of calculating parameter g . On the other hand, the different Mass functions denote the varied experts’ options for the same thing, and the authorities of varied experts are different. But until now, There does not exist a method which combines two different weighted mass functions. Based on the above research results, this paper provides a method which can combine two different weighted mass functions.