Aiming to tackle the issues of high labor intensity and low efficiency associated with manual removal of residual plastic film from straw feed in Xinjiang, a needle-belt type electrostatic separation device for residual plastic film in straw feed was designed. Based on the principle of electrostatic adsorption, the device consisted of core components, including a high-voltage electrostatic generator, electret discharge rod, and metal conveyor belt. Through theoretical analysis, the critical conditions for separating residual plastic film from straw feed were deduced, verifying the feasibility of applying the needle-belt type electrostatic separation technology to residual plastic film removal. Using COMSOL simulation software, the effects of geometric parameters and operating parameters of corona needles on electric field distribution and negative ion density were studied, and the optimal parameters were determined as follows: needle tip cone angle was 12°, needle length was 14mm, and needle spacing was 20mm. Single-factor experiments showed that the electrode spacing (40~60mm), voltage (15~25kV), conveyor belt speed (21~28m/min), and material feeding rate (8~12kg/min) had significant impacts on the separation efficiency. A quadratic regression model was established by using the Box-Behnken experimental design, and the optimal parameter combination of the device was determined as follows: electrode spacing was 51.3mm, voltage was 22.9kV, belt speed was 24.5m/min, and feeding rate was 9.5kg/min. Finally, the separation efficiency measured in the verification experiment was 91%, which was in good agreement with the predicted value of 92.6%, meeting the technical requirements for removing residual plastic film from straw feed.