Abstract: To meet the requirements for transonic high-load aerodynamic tests of a linear cascade, a numerical simulation method was taken to investigate the uniformity of inlet flow field and periodicity of cascade channel flow field in a high-load turbine rotor cascade with varying inlet flow angles of incidence and outlet isentropic Mach numbers. The results indicate that the inlet flow field of linear cascade presents an uneven trapezoidal distribution along the circumference, and the inlet flow uniformity and accuracy of the three passages near the suction side wall are generally poor, while the inlet flow uniformity and accuracy of the passages near the middle of the cascade and the pressure side wall are better, the quality of inlet flow field directly affects the periodicity of flow field in the cascade channel, and the influence of inlet flow angles of incidence on the quality of inlet flow field is more obvious than that of outlet isentropic Mach number. Under the positive angle of incidence, the angle of incidence deviation is about 0.7°, and the uniformity and accuracy of inlet flow field of different cascade passages are better. From subsonic flow to supersonic flow, the cascade channel near the suction side wall of the test piece produces strong shock waves, leading to an increase in pressure error at 80% axial chord length of the blades and a decrease in the periodicity of the cascade channel flow field.