The invention relates to a novel integrity analysis method for a reactor coolant pump impeller. The method includes the steps that blade pressure distribution measured by an impeller hydraulic model test is simply analyzed, assuming that the pressure tendency from the tip of an impeller blade to the root of the blade is in linear radial slippage, zero-pressure slippage is conducted in the peripheral direction, blade inlet edge pressure measured by the impeller hydraulic model test is imported into Ansys, real turbine axial force is divided by axial counter-acting force to obtain a pressure load factor, and the pressure load factor is multiplied by the model test inlet pressure distribution to obtain real turbine inlet pressure distribution. By calculating the load periodic cycle borne in the whole operation cycle of the impeller, the raw material performance parameters of the impeller and the operation condition temperature of the impeller are corrected to obtain the fatigue limit under the cyclic cycle condition; and the operation condition of impeller loads is optimized, the safety factor at the maximal stress amplitude under the corresponding load condition is obtained by means of calculation to be subjected to contrastive analysis with a designed safety factor, and accordingly the fatigue safety is confirmed.