Abstract: A modified differential evolution algorithm(DE) is presented for solving circles packing problem with constraints of equilibrium in 2-D space.Firstly,the method constructs an equivalent physical model and defines the energy function of the system.Then the DE optimizes the energy function globally and the approximate solution is obtained indirectly.Strategy of adjusting parameters dynamically maintains diversity of the individuals at early stages and expedites convergence speed of the algorithm at latter stages,thus the performance of DE algorithm is improved.Finally,two examples are computed numerically,and the experiment results show that the algorithm is effective.The strategy in this paper can be applied to solve other layout problems.