NVH stands for Noise, Vibration, and Harshness and is widely used to evaluate various vibration and noise phenomena that may occur in mechanical systems. For example, in the case of automobiles, NVH analysis is used to determine vehicle noise and ride comfort of vehicles, especially cars and trucks. There are many kinds of excitation sources such as transmission noise and vibration, tire resonance or imbalance, road irregularities, various vibration components of an electric motor, and noise and vibration due to an unbalanced mass of a washing machine. There are various methods of NVH analysis using CAE. This study introduces mainly focus on the NVH analysis methods using multi-body dynamics. Since many mechanical systems operate under dynamic conditions, NVH analysis using multi-body dynamics is important and useful. This study will introduce the methods such as system eigenvalue analysis, modal analysis of a single component, FRA (frequency response analysis), and resonance phenomenon confirmation through multi-body dynamics simulation. Also, how to review the NVH analysis results are shown with two example models. One example is 1-DOF shaker which includes a flexible structure and a rigid body. Firstly, the modal analysis result of the single component (flexible structure) is obtained, and it will be compared with the eigenvalue analysis result of the multi flexible body system. After that, the vibration characteristics for the transient behavior are analyzed through animation, contour plot, and vibration shape using the multi flexible body dynamics simulation. The other example is gearbox reducer which consist of one helical gear set and one planetary gear set. The vibration characteristics of the gearbox reducer will be analyzed when the input rotation speed changes from 0 to 4000 RPM. Especially, this model will include the vibration effect of the characteristics of the motor and inverter. The vibration characteristics which involve both of mechanical vibration and electrical vibration can be obtained through the Campbell diagram. And EPR (Equivalent Radiation Power) result and Vibration shape of the gearbox reduce simulation will be shown.