GdTaO4 and LuTaO4 are heavy scintillators with fast decay fluorescence. The photoluminsecence spectra of M phase Nd∶GdTaO4 and M′ phase Nd∶LuTaO4 excited by a laser diode (LD) of 808 nm were fitted with the full-profile fitting method, and the transition intensity parameters Akt,p were determined. Under the excitation of 808 nm LD laser, the population ratio between the upper and low crystal field energy levels of 4F3/2 for Nd3+ in GdTaO4 is near to 1, but in LuTaO4 is 1.30 and 1.41, which indicates that the relaxation rate between two crystal field energy levels is nearly equal to the excitation rate of LD. The Judd-Ofelt transition intensity parameters Ωt were calculated with Akt,p, and the transition probabilities from 2P3/2 of Nd3+ in GdTaO4 and LuTaO4 were computed, which indicates that the fast decay fluorescence of several hundred nanoseconds of Nd3+ in GdTaO4 and LuTaO4 is caused by the high nonradiative transition.