ABSTRACT Fan cooling is a fairly mainstream and well-developed technology. Vibration may make users feel uncomfortable. Assembly system may produce different noises right after the adverse effect components were destroyed, such as computer crashed or vibration or fan structural damage subsequently affects their fan reliability. Therefore, small vibration resonance amplification can not be overlooked. The researcher applied a 40 * 40 * 48mm fan to solve the problem of resonant vibration. He found the similar results of the natural frequencies of the structure of the fan by experimental and finite element analysis. In order to improve the vibration resonance, he changed the structural of the fans. In different structural designs, the natural frequencies did not change a lot. The natural frequency switched from 3000Hz to 3200Hz. To avoid the resonant frequency of the assemble fan, the researcher changed the number of fan blades and simulated the flow field. Compared the data to the experimental results, the results of the analysis were reasonable. The results showed the performance of the assembly fan did not necessarily need more leaves. The leaf numbers were from 7 (Inlet Fan) & 4 (Outlet Fan) into 5 (Inlet Fan) & 4 (Outlet Fan). Operation speed was changed from 14500 rpm (Inlet & Outlet Fan) to 15500 rpm (Inlet Fan) &11600 rpm (Outlet Fan). Using the fluid flow analysis, he found the change of the leaf number and operation speed of the fan could effectively avoid the resonance frequency and reduce vibration. An impact analysis was also helped to verify the capacity of the anti-impact of the fan. The structure of the fan after the preliminary design has been shaped mostly. By only changing the structural design to avoid excitation of the resonant frequency is difficult to achieve the effective function. To ensure the product stability, it is necessary to deal with the inducing vibration of the fluid flow.