In order to meet the needs of collaborative operation of cotton stalk returning to field and residual film recovery in Xinjiang cotton area, aiming at the problems of low qualified rate of cotton stalk crushing and high falling rate of crushed materials in the operation of existing cotton stalk crushing-residual film recovery machine, a Y-type cutter-tooth cotton stalk crushing and returning device with front-mounted residual film recovery machine was designed. The device can effectively improve the qualified rate of cotton stalk crushing, reduce the falling rate of crushed materials and reduce the occurrence of conveying blockage through the collaborative operation of cutter-tooth blade crushing and screw conveyor side throwing. The working principle of the device was expounded, and the structural optimization design of key components such as knife-tooth flail and screw conveyor was carried out. The trajectory equation of the flail was established, and the influencing factors of operation of crushing device were determined. The MBD - EDEM multi-body dynamics-discrete element coupling simulation was used to establish the interaction model between the crushing device and the straw. The number of flails, the rotation speed of knife shaft and forward speed were selected as the experimental factors. The three-factor and three-level simulation test was carried out with the cotton stalk crushing pass rate and the crushing drop rate as the evaluation index. The test results showed that when the screw flail was 32, When the rotation speed of the cutter shaft was 2 100 r/min and the forward speed was 1.5 m/s, the crushing performance was better. The qualified rate of cotton stalk crushing length was 93. 05%, and the crushing drop rate was 2.5%. The cutter shaft was analyzed under the optimal combination. The modal analysis of the cutter roller was carried out by ANSYS. The natural frequeney of the lowest order of the crushing cutter roller was 73. 541 Hz, which was much higher than the working frequency (31. 67 ~ 38. 33 Hz), and no resonance occurred. The simulation results shoved that the device structure and operating conditions met the design requirements. The field test results showed that the qualified rate of cotton stalk crushing was 94.3%, the unevenness of scattering was 13.8%, and the average stubble height was 75.6 mm, which were better than that of the national standard requirements.