The four-dimension program including time were used to simulate incomplete phase conjugation for laser propagation in turbulent atmosphere.The reflectivity of the beacon with different aperture were compared,the dependence of reflectivity and fidelity of phase conjugation beam of the hard aperture on the turbulence structure constant by different beacon aperture deliverinig different range in the condition of middle and weak turbulence,and the dependence of reflectivity and fidelity of phase conjugation beam of the soft aperture on the Gaussian aperture W by different beacon aperture in the condition of strong turbulence were investigated.It was showed that 0.5 m accepting aperture could provide ideal compensation to point beacon up to 3 km propagating distance underthe condition of middleand weak turbulence;and the bigger beacon had higher fidelity and it needed much lower system magnification than that of the smaller beacon when the propagating distance was 3 km under the condition of middle turbulence of C_n~2=10~(-15) m~(-2/3);on the contrary the bigger beacon had lower fidelity than that of the smaller beacon,meantime the PCM with smaller aperture could get higher fidelity when the propagating distance was 3 km under the condition of strong turbulence of C_n~2=10~(-13) m~(-2/3).