This paper discusses the performance model for practical computational fluid dynamics (CFD) simulation. Based on the analysis of the conventional qualitative model and empirical knowledge in the simulation, a set of practical models for the linear solution in high-order finite element method (FEM) simulation are established: a linear function model for the storage consumption, and a power function model for the solution time. The unknown parameters in the models are estimated by linear fitting and nonlinear fitting, respectively. Tests on a typical high-order FEM platform show that the proposed models are highly accurate and practical. In addition, it has been tested that nonlinear fitting is better than linear fitting in our case.