The millimeter accuracy of a satellite laser ranging (SLR) system is often hindered by the satellite signature effects. Based on the actual distribution of the satellite retroreflectors, the retroreflector uneven distribution (RUD) model is proposed in this study. The relationships between laser incident angles and the number, distribution, and reflection intensity of the retroreflectors that have participated in the SLR reflection are calibrated and discussed, while the effects of satellite signature on the echo signal residual and center-of-mass correction (CoM) are analyzed in detail. Results indicate that compared with the common CoM model, the participant retroreflectors are dispersedly and asymmetrically distributed, and their number is a function of laser incident angles. The reflection intensity for each reflector at the same satellite latitude is different and the retroreflected pulse is observed to be broader than the transmitted pulse with significant tailing effect. The above results agree with the experimental results. In addition, the CoM value obtained using RUD model dynamically varies with the laser incident angle. For Lageos-1, the average CoM of Changchun Station is 248.1 mm, which is consistent with the reference range accepted by the international laser ranging system.