Abstract: To study the effects of the motion parameters of rubber-roller harvester on cotton harvesting performance in Xinjiang cotton planting pattern, the harvesting principle and the components of rubber-roller harvester were introduced in this paper. The functional relationships between the speed ratio and the harvest angle of rubber-bar, the absolute velocity and the roller speed were established based on the displacement and velocity equations of rubber-bar end, and the influences of speed ratio on cotton harvesting performance were analyzed. Experimental results showed that the collect rate of cotton was over 95%, the percentage of impurities was less than 15% and the percentage of landing cotton was less than 2% when the roller speed was 450 r/min and the working speed ranged was 0.83 m/s. The rubber-roller harvester can meet with the requirements of mechanized harvesting cotton.