There is a lack of soil loosening components suitable for grassland ploughing. To better break the compacted structure of grassland soil, a special soil loosening component for grassland was designed: a folded-wing subsoiler. Optimization of the combination of structural parameters was carried out by using the shank slip angle, wing width and tip entry angle of a folded-wing subsoiler as test factors, and tillage resistance, furrow contour area and ridge contour area as target parameters. The working performance (ridge contour area, pit contour area, soil disturbance coefficient, soil bulkiness, turning rate, and surface flatness) of the folded-wing subsoiler and three traditional subsoilers (chisel point, diamond point, and arrow point) in grassland soil was compared. The test results showed that the optimal combination of the structural parameters of the folded-wing subsoiler was as follows: the wing width was 40mm, the shank slip angle was 20°, and the tip entry angle was 20°. At this point, the optimal solution for the objective values was 6140N of tillage resistance, 160cm2 of pit contour area, 68cm2 of ridge contour area. Compared with the three traditional plough points, the surface of the grassland after the operation of the folded-wing subsoiler was more flat, and there were fewer turning pieces, and all of them were small pieces of soil; at the same operating speed, the pit contour area and soil disturbance coefficient caused by the folded-wing subsoiler were the largest, while the ridge contour area, soil bulkiness, turning rate and surface flatness were the smallest. Therefore, the grassland loosening performance of the folded-wing subsoiler was better than that of the traditional chisel point, diamond point, and arrow point. The research results can provide technical reference for the creation of key tillage components suitable for mechanized improvement of compacted grassland.