Neutron activation experiment is one of the important experiments in undergraduate experimental education. For further guiding students to dig experimental data，the half-life of fission nuclide ( 89 Rb)is measured simultaneously. In this paper，the fission reaction of 238 U induced by 14 MeV fast neutrons is carried out. The γ-ray energy spectrum of the fission products is determined by a low background HPGe ! γ spectrometer，and the half-life of 89 Rb is determined. In the data analysis，the two gamma rays of 89 Rb nuclide are independently used to obtain the half-life of 89 Rb of 15.30±0.09 min and 15.25±0.07 min. The measurement results are in good agreement with the data reported in the literature. This work improves the accuracy of the half-life of 89 Rb.