This paper presents the limit loads, J integral results and failure assessment curve (FAC) for the circumferential through-wall cracked isotropic and orthotropic pipe of pure titanium TA2. Limit loads, J integral and curves were calculated based on the 3-dimensional (3-D) elastic-plastic finite element (FE) analyses. Geometric variables of pipe and crack size are systematically varied. Effects of the orthotropy on failure assessment curves are considered. Calculation results show that the limit load and J integral of isotropic pipe and the anisotropic pipe are obvious different. For failure assessment curves, when the load ratio Lr < 0.9, if the orthotropic material is evaluated as an isotropic material, the evaluation results are conservative. When the load ratio Lr > 0.9, if the orthotropic material is evaluated as an isotropic material, the evaluation result is too dangerous. And it is the most dangerous when the mechanical properties of the axial direction are stronger than those of circumferential direction. Thus the orthotropy of circumferential through-wall crack pipe cannot be neglected for defect assessment.