Abstract: In view of the low efficiency of collecting and bundling rice and sugarcane straw using small straw round balers, the situation of indoor bundling of round balers is studied to provide necessary theoretical and technical basis for the structural improvement of round balers. Whether the straw can form a straw core smoothly in the bale chamber is mainly related to the friction coefficient between the roller and the straw. Using the self-made sliding friction coefficient test device, the friction characteristics of the straw are tested and studied, and the orthogonal rotation combination of three factors and three levels is used. The experimental design plan explored the influence of three variable factors of straw moisture content, sampling location and slide material on the friction coefficient. The results showed that the moisture content has the greatest impact on rice stalks, and the slide material has the greatest impact on sugarcane leaves. Among these three slide materials The friction coefficient between the rubber and the rubber is the largest. Conclusion: the lower part of the roller in the small round baler bundling chamber can be considered to use rubber to adhere to the zigzag convex surface of the steel roller. This kind of rubber roller is more beneficial to the rapid formation of the grass core.