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According to the existing problems of subsoilers applied in loam soil area in NorthChina Plain, such as high working resistance, high fuel consumption, poor surface flatness and poor soil moisture conservation due to the formation of crack after subsoiling, a polyline soilbreaking blade subsoiler which could effectively reduce working resistance and fuel consumption was designed based on the difference of soil layer thickness and physical properties among plough layer, plow pan layer and subsoil layer. Discrete element method(DEM) was used to establish soil model, the soil particle contact model was set, and virtual simulation parameters of different soil particles in plough layer, plow pan layer and subsoil layer were measured. A virtual simulation experiment on subsoiler performance was conducted using EDEM. As shown in the result, minimum working resistance was detected when the rake angle (θ) of soilbreaking blade was ranged from 40°~45°; minimum power dissipation was obtained when the corresponding shearing angle (φ) to the higher, middle and lower parts of soilbreaking blade were 31°, 36°, 33°, respectively; when comparing with circular arc subsoiler, polyline soilbreaking blade subsoiler resulted in less impact on soil particles, reduced soil disturbance, decreased tractive resistance, significantly improved surface flatness and groove width. The field test indicated that the polyline soilbreaking blade subsoiler effectively decreased soil bulk density and compactness of plow pan layer, hence the working resistance was reduced by 11.52% with better working stability and reliability with comparison to circular arc subsoiler. The rationality and feasibility of threelayer DEM soil model was confirmed through the comparison of field test and virtual simulation experiment, and the model could satisfy the requirement of subsoiler performance experiment.