A segment scaled model is produced based on the double tower concrete cable-stayed bridge as the engineering foundation to study the fatigue performance of large-span partially prestressed concrete (PPC) cable-stayed bridges with cracked main beams. The cable force and prestressing force of the main beam of the segmental scaled model were adjusted to partial prestressing state based on the results of finite element calculation. The fatigue performance test research of PPC cable-stayed bridge with cracks was carried out after preloading the segmental scaled model to a certain damage. The fatigue test parameters were designed by combining the real bridge load spectrum, and the fatigue load was determined as 22-34 kN with a loading frequency of 1.5 Hz, and the cyclic loading was 2.5 million times. The static load tests were carried out on the model beam under different cycle loading times. The test results indicated that the cracks of the main beam were in a "closed-open-closed" cyclic process during the fatigue loading under the condition of pre-damage. The deflection of the main beam in static load tests increased steadily with the increase of fatigue loading times. The degradation of the system stiffness at L/4 (L is span), L/2 and 3L/4 sections of the main beam was 5.08%, 5.19% and 6.63%. The cracks in the main beam developed smoothly, and the crack width expanded from 0.04 mm to 0.06 mm, and all the cracks were closed after unloading under the peak load condition of the static load with different loading times. The cable force was basically unchanged under the same load condition, and the stayed cable was basically undamaged in the static load test. In conclusion, the system stiffness of PPC cable-stayed bridge decreases slowly under the condition of main girder with cracks. There is no obvious degradation of stay cable stiffness. The bearing capacity of the system can still meet the requirements of normal use.