Based on the representation of impulsive sound propagation with the moving source and receiver, a seafloor reverberation signal model is derived from the monostatic sonar moving horizontally in horizontally stratified oceans. Then, a method for simulating reverberation time series is presented with the seafloor divided into range-azimuth cell. It is found that the method can effectively solve the problem that correlated scatter coefficient between different normal modes is difficult to be expressed, and the delay-doppler distance for any cell is less than rated resolution. The power spectrum and the probability density of simulation results show the validity of the modeling and simulation method.