By using the algebra method of building body-fitted coordinate,a trapeziform region was transformed from physical domain to conputational domain,and the boundary conditions were also transformed from physical domain to computational domain accordingly.The body-fitted transformation equation was used to disperse and compute the dominate equation of temperature filed,producing the body-fitted grids of the physical domain of the trapeziform region.Simultaneously,it was applied in nonorthogonal curvilinear coordinate systems to simulate and compute the temperature field by orthogonal curvilinear coordinate systems under the same conditions.So the validity and feasibility of nonorthogonal curvilinear coordinate methods were illuminated.