With a transmission system suitable for a medium or large self-propelled cotton picker as the object of the study,the following work focuses on the influence law of an independently designed hydro-mechanical continuously variable transmission (HMCVT) in the process of changing sections.An HMCVT simulation model was established using the multibody dynamics Simulation X software.The accuracy of the simulation model was verified by comparing the numerical values of the output speed of the HMCVT with model predictions.The HMCVT test bench was built independently using a John Deere 4045HYC11 diesel engine as power input.The engine speed,load torque,oil pressure,and flow of speed regulating valve were considered the influencing factors.The sliding friction power was the response index for the segment change process test.We analysed the reasons for the decrease in output speed during the shifting process,and proposed to effectively reduce the stable speed difference before and after the output shaft shifting by shifting the stage ahead (with displacement ratio of-0.96).This study provides a reference value for the smoothness of the HMCVT of the self-propelled cotton picker,and is relevant in promoting the use of the cotton picker.