Strength plays an important role in structural integrity and safety for explosive parts, and is also the basis for estimation of the structural strength. Based on uniaxial loading technique, strength property of TATB based polymer bonded explosive(PBX) under triaxial tension stress state was studied by an end-restraint cylinder tension collapse method. The stress field under critical load was quantitatively analyzed through finite element simulation according to the tested boundary conditions. At last, the adaptability of three typical criterions(uniaxial-strength, Mohr-Coulomb, twin-shear) in strength analysis was illustrated using principal stresses of initial failure position. Results show that among these three criterions, uniaxial-strength criterion, which is most often used in explosive engineering, has the best safety threshold, about 43.77%, under triaxial compression stress state, but even so, it still can not supply a safety forecast for this TATB based PBX strength failure under triaxial tension stress state. For the representation accuracy, uniaxial-strength criterion has the best precision with an error about 16.90%, Mohr-Coulomb criterion and twin-shear criterion take second and third place with the error of 19.62% and 24.56%, respectively. Moreover, the triaxial tension strength is 0.831 times of the uniaxial tension strength, while Mohr-Coulomb criterion can not predict the strength lower bound precisely. It may be mainly caused by hydrostatic pressure, which must be considered further to establish multiaxial strength criterion with high precision.