In conventional pseudo-spectral method for solving the wave equation, the routine algorithm needs large quantities of computation and spends a long computing time. In this paper, the authors have integrated the pseudo-spectral method to raise the accuracy and efficiency, and improved its conventional algorithm of calculation constants which need multiple calculations in the Fourier transform and inverse transform in the procedure of calculation. These constants are brought out of the time loop structure, thus avoiding the duplication of many calculations and reducing the number of calculations. In this way, the computational efficiency has at least been doubled. Considering the importance of subtle traps in the oil and gas exploration, the authors have constructed a special structure for the subtle traps, namely the lens model. This algorithm was used to simulate cross-well field characteristics of high-velocity and low-velocity lens models and make a comparative analysis of synthetic cross-well seismic records, time slices and amplitude characteristics of the two models. The result is in good agreement with that of theoretical analysis.