The complex structure of polymer gels was studied with dynamic Monte Carlo simulation based on the principle of gelation theory in a 2D network with periodic condition. The effect of polymerized monomer's (monomers of polymer) movement on the structure of polymer gels was studied. Simulation results indicated that the threshold concentration of gelation and the fractal dimension of polymer gels could be considerably decreased compared with the kinetic gelation model and the DLA model when polymerized monomere were allowed to move

especially when the total monomer concentration is low. The pore size distribution was acquired by moving bubble method. It was found that the ratio of big pores in our gel network was higher than that based on the Ogston's model.That indicates the simulated gels was of great inhomogeneity.