Aiming at the problem of excessive vibration of the multi-rotor drone, which causes instability of flight state, the vibration reduction analysis work was carried out based on finite element simulation technology and experimental methods. Through frequency analysis, the reason of excessive vibration was determined to be resonance caused by coupling of natural frequency and excitation frequency,and the mode shape corresponding to the resonance frequencies were the first-order waving, the first-order swing and the second-order swing mode shapes. An optimization design method for optimizing the cross-sectional shape of the drone was proposed. Without adding extra weight, the corresponding frequency points of the first-order waving mode, the first-order swing mode, and the second-order swing mode have been increased by 37.23%, 22.47% and 18.43%, respectively. Simulation experiments prove that the proposed vibration reduction analysis and optimization design method can provide references for design work of drones.