The nonlinear effect equations describing intra-channel four-wave mixing and intra-channel cross phase modulation in high-speed quasi-linear optical transmission system were deduced first, then the simulation model was built. Based on this model set, the quasi-distributed dispersion compensation solution and the lumping dispersion compensation solution were compared. Lastly, the trends of nonlinear interactions changing with bit rates were acquired by analyzing the performance of quasi-linear optical transmission systems with different bit rates.