To solve the problem that the reliability of transformer protection tripping is not high because abnormal sampling data and excitation inrush current cannot be identified properly in smart grid, this paper puts forward a research scheme about sampling data reliability and inrush current identification of transformer protection. For the problem of abnormal sampling data, it gives a method which uses double AD sampling data to real-timely check each other and control protection logic outlet together. At the same time, for excitation inrush current identification problems, it proposes a method of differential current harmonics mutually atresia plus synthesis harmonic open by phase on no-load energizing and secondary harmonic low “two out of three” by phase differential current when restorative excitation inrush current happened. Simulation results verify the effectiveness of inrush current identification scheme.