Cadmium telluride (CdTe) is one of the most attractive photovoltaic materials due to its low cost, high efficiency and stable performance in physical, optical and electronic properties. Few researches on the influences of uniform surface on the photovoltaic characteristics in large-area CdTe solar cell were not reported. As the preceding study of the effects of thickness-uniformity on the photovoltaic characteristics for the large-area CdTe thin film solar cell, chemical mechanical polishing (CMP) process was investigated for an enhancement of thickness-uniformity. Removal rate of CdTe thin film was 3160 nm/min of the maximum value at the 200 $gf/cm^2$ of down force (pressure) and 60 rpm of table speed (velocity). The removal rate of CdTe thin film was more affected by the down force than the table speed which is the two main factors directly influencing on the removal rate in CMP process. RMS roughness and peak-to-valley roughness of CdTe thin film after CMP process were improved to 96.68% and 85.55%, respectively. The optimum process condition was estimated by 100 $gf/cm^2$ of down force and 60 rpm of table speed with the consideration of good removal uniformity about 5.0% as well as excellent surface roughness for the large-area CdTe solar cell.