The 76 mm×76 mm LaBr3 crystal doped with CeCl3 was grown by modified Bridgman technique. The crystal was cut and ground to 76 mm×15 mm, and packed in a housing to prevent hygroscopic effects. The entrance window was comprised of a 200 μm thick Be sheet. The energy resolution of package is 55% under 5.9 keV gamma-ray excitation. The scintillation performance of the package was characterized before and after mechanical test (1 000 g impact and 14.12 g random vibration), thermal vacuum test (-40~+50 ℃, ≤1.3×10-3 Pa), and irradiation test (160 krad dose of 60Co irradiation). The results show that there is no change in the appearance of crystal. The energy resolution of the package changes from 5.30% to 4.89% under 662 keV gamma-ray excitation, the light output loss is 0.2%.