An irregular discrete element simulation method using signed distance field (SDF) to detect the contact between particles is proposed to analyze the dynamic behavior of irregular particle systems. The contact detection of irregular particles is the key difficulty. In the coarse detection stage, the neighbor particles were retrieved by the spatial sorting method. In fine contact detection, the SDF implicit function is used to describe the irregular shape of the particles, and the signed distance of the voxel grid generated on the surface of the particles is linearly interpolated to extract the contact characteristics of the particles efficiently. The effectiveness of the proposed method is verified by the comparison between numerical simulation and experiment of particle collapse.