Abstract: The neutron transport SP₃ equation was solved by high order generalized transverse integration nodal method (GTIN), in this paper the GTIN method is used to solve the neutron diffusion equation. The transverse leakage approximation in traditional transverse integration nodal method is eliminated by this method to improve numerical accuracy. Besides, the nodal interior neutron flux distribution information can be used directly for core pin power reconstruction by GTIN method. The IAEA 2D/3D and LMW 3D benchmark problems are solved, numerical results indicate that GTIN method can achieve higher accuracy than traditional nodal method and better pin power reconstruction result.