The optimizing design is the most important composition of the modern design，and Genetic Algo-rithms is one of the optimization design methods.Based on the experienced formula of aluminum cutting，by sim-ulation through Definite Element Analyzing software Ansys10.0，the deformation of workpiece under different machining parameters can be obtained;optimizing the processing parameters by Genetic Algorithms through toolbox MATLAB7.0，the least deformation and parameters can be acquired.The results would play a guiding role in the production and processing.