Abstract: The performance of the polythene film collector was analyzed, and the design of the loosening shovel was developed. The loosening shovel is one of the key components of the polythene film collector. It is used for separating the film and soil, which is important process in order to ensure the better cdlection of plastic film. The process included loosening plastic film, separating the film and soil and turning over stubbles. When collecting polythene film, the loosening shovel cuts in side film, loosens soil, separates the film and soil, and cuts off stubbles conveniently. The structure of the loosening shovel was introduced, and the location of the loosening shovel to adapt to the film working width of different crops was considered. The performances of dimension parameters and working parameters were studied. The best parameters were computed by nonlinear optimization with MATLAB. After adjusting the designing parameters,the loosening shovel was tested. The loosening shovel is simple in structure and easy to make.