Fixed-point simulation is extremely important in the design of fixed-point FPGAs (Field Programmable Gate Arrays). Float-point simulation is used to verify the arithmetic, while the fixed-point simulation is adopted to evaluate the performance and verify the implementation. The design of high-precision system based on FPGAs must focus on the fixed-point simulation to reduce the error acceptable even to zero. Basing on the analysis of fixed-point simulation approaches, especially the approach with MATLAB fixed-point toolbox, the authors propose a novel fixed-point simulation library consisting of four modules.