This talk concerns an inverse source problem for the biharmonic wave equation. A two-stage numerical method is proposed to identify the unknown source from the multifrequency phaseless data. We first establish a phase retrieval formula by introducing some artificial auxiliary point sources to the inverse source system. We show that the phase can be uniquely determined and estimate the stability of this phase retrieval approach. Next, the Fourier method is adopted to reconstruct the source function from the phased multifrequency data. Numerical results will be presented to illustrate the performance of the proposed method.