Abstract: The vibrations in the line-spectrum of the floating nuclear power station pumps (the typical pump) are notable during the system operation, which increases the vibration level of the whole system. In this paper, taking the vibrations in the specific frequencies at 49 Hz of the typical pump as the research object, a dynamic vibration absorber is designed. Based on the related factors such as the system operation environment, dynamic vibration absorbing principle and installation method, this paper initiates the design parameters of the vibration absorbers, and then explores the effects of geometrical parameters, mass, damping on vibration absorption frequency band. The FEM model of the typical pump with dynamic vibration absorber is developed, which verifies the absorbing effect of dynamic vibration absorber.  The effects of mass, damping and numbers of the dynamic vibration absorber on absorbing effect are analyzed. The results show that the dynamic vibration absorber can be adjusted within the frequency range of 8~400 Hz after adding the dynamic vibration absorber, and the absorbing effect in the line-spectrum vibration of a typical pump at 49 Hz can reach 7.3 dB.