The two-degree-freedom vibration system made of the main mass and dynamic vibration absorber was studied. The mathematic model was built based on the principle of D'Alembert theory which was calculated with non-dimensional equations. Aiming at four parameters （κ，γ，δ，μ）of the dynamic vibration absorber，the optimal design of parameters was processed with Davidon-Fletcher-Powell(DFP) method of variable metric, penalty function method and line-search method. The calculating methods were implemented by the program of Matlab and Visual C++. The results show the convergence situations of four parameters. The parameters of γandδ tend towards the upper limit of the defining regions, whileμ andκ tend towards the fixed values respectively. The conclusion is significant to the parameters design of dynamic vibration absorber in actual application and controlling of the vibration.