Reducing the rate of stubble pushing (Ratio between the pushed stubble area and the area of harvesting) by chassis of the completely tracked harvester in the mechanical harvest processing of the first crop of the ratoon rice can not only ensure the yield, but also improve the quality of the ratoon rice. Based on the tracked vehicles design theory, six influential factors were chosen to analyze: the width of the cutting range Z, the track gauge B, the length of the track on ground L, the width of the track b, the turning radius R0 , the longitudinal distance between the central axis of chassis and cuter of cutting platform X. Both a structure model of the chassis of the completely tracked ratoon rice harvester and a stubble pushing model (going straight and turning) in the field were established. Furthermore, a rice planting model was set as follows: its planting row spacing was i, hill spacing was c, and hill diameter was br in the field. And then the influences of various parameters on the stubble pushing rate were analyzed. Under the same planting conditions and the parameters of the completely tracked harvester, the results showed that the stubble pushing rate δ1 decreased with the ratio of Z to b increased when the harvester was on straight way; while on turning way, the δ2 decreased with the turning angle θ and R0 increased.