For the purpose of reducing noise from the vibration of range hood’s shell, the vibration response of it is calculated based on the finite element model of range hood’s shell when excited by the motor. Then, the optimal geometric design of the structure is preformed using the peak particle velocity at four sensitive nodes as the objective function during which the thicknesses of the four parts are adopted as the designing variable. In addition, the weight of the structure is kept no more than its original weight. The particle velocity is calculated by using the commercial software Nastran and the DOE method is utilized to obtain the optimized shell thickness. After which, the particle velocity peak of the designed area is decreased more or less and a maximum 8.2 dB reduction of vibration velocity level can be obtained. Results show that the changes of the four part’s thicknesses can reduce the radiating noise of the range hood at the condition of no increase of the shell’s weight.