Thermo-elastic singularities of V-notches in orthotropic materials are studied. By introducing series asymptotic expansions of physics fields near notch tip, stress and flux equilibrium equations are transformed into characteristic ordinary differential equations with respect to singularity orders. Singularity orders and corresponding characteristic angular functions can be derived synchronously as interpolating matrix method is introduced to solve characteristice quations. The method evaluates stress and flux singularity orders at the same time. Numerical results show that it has high accuracy and strong adaptability.