An efficient method for estimating the range of forming force for an upsetting-extruding process was proposed, which may be useful to choose appropriate forming equipment. The accurate prediction of the forming force of an upsetting-extruding process is the key to form a work piece successfully. However, the forming force is variable in a certain range for the variation of material and process parameters. In general, the variation is dominated by some of the main effects and lower-order interactions due to the sparsity-of-effect principle. Therefore, the construction of polynomial chaos expansion with points of monomial cubature rules, which need fewer points than other kinds of integral, is particularly attractive in dealing with computational model for the forming simulation. An automobile threated plate is used to illustrate the validation of the method.