Aiming at the problems of complex and harsh working environments and low reliability of the working arm of the anchor drilling robot, the dynamic characteristics of the working arm are studied based on the dynamic simulation analysis and vibration test analysis. In view of the influence of working load and deformation on the rigidity of the working arm, the static finite element analysis is implemented by simulating the actual working conditions. The stress and strain distribution of the working arm under the roof anchor drilling condition is derived, and on this basis, the modal analysis of the working arm with pre-stress is carried out. The six orders of vibration mode and the corresponding inherent frequencies are obtained. A vibration test system of the working arm is set up to achieve the three-dimensional vibration accelerations of the working arm under the roof anchor drilling condition. The fast Fourier transform of the vibration acceleration signals is conducted to obtain the vibration spectrum. The dynamic characteristics of the working arm are analyzed through the vibration frequency and the inherent frequency, which is of great reference value for improving the reliability of the working arm.