In this paper, a special beat phenomenon of metal nanowires is investigated by using the large scale molecular dynamics simulations. It is observed that the beat phenomenon exists not only in the vibration of 〈1 1 0〉 orientated Face Center Cubic (FCC) nanowires of different materials, but also in the vibration of 〈1 0 0〉 orientated Body Center Cubic (BCC) nanowires. Based on the atomic arrangement, a discrete spring-mass model is developed to explain the displacement characteristics of nanowire’s vibration. It is found that the vibration frequency of nanowires rises slightly with the increase of initial actuation amplitude. The displacements of a typical atom in the nanowire are used to show the dynamical characteristics of beat phenomenon in vibration experiments. In addition, the beat phenomenon driven by a single actuation along one of the elementary directions has also been observed and shown in this work. Furthermore, a theoretical analysis is given for the excitation mechanism of beat phenomenon by analyzing the relation of excitation frequency between the two elementary directions.