Abstract: A computer simulation for evolution of random structures of spherical particles in two dimensions has been performed by the distinct element method. The forces among the particles considered were gravity, friction force and Van Der Waals Interaction(VDWI). The motion of particles involved translation and rotation. For 100 μm particles, if friction and VDWI were not considered, the packing assembly was a mixture of random packing and order packing with packing density of 0.869 6, if friction and VDWI were taken into account, the packing density was 0.821 3. To study the procedure of packing, packing densities with different time, particle trajectory and coordination number were examined. The packing structures of binary system with different conditions were also given.