Etalon satellite is regarded as one of the most promising tools for studying crustal motions, Earth rotation and other scientific applications. Unfortunately, its outsized shape and signature caused an adverse satellite signature effect on its range accuracy. In this study, we use the Retroreflector Uneven Distribution Model to simulate the echo signals sent from Etalon and figure out how the value of the corresponding center of mass corrections changes according to the incident angles. A center mass of correction filter has been proposed and implemented in the standard SLR data processing to eliminate satellite signature effect from the distribution of the post-fit residuals of Etalon. The measurements with minimum variability are selected by modifying the rejection criterion of effective returns. The statistical results of our study reveal that the new algorithm has a significantly better ranging accuracy. The mean RMS of normal points has been reduced from 163.7 ± 41.8ps to 118.2 ± 8.94ps, while the stability of the collected data has been improved by 79%. In addition, the new algorithm is able to improve the range accuracy of Etalon-2 by almost identical proportions. This method seeks to minimize the range bias induced by the variations in satellite signature effect at different incident angles, which provides a theoretical reference for the research on millimetre level satellite laser ranging.