Neutrino detection in the 100 PeV energy region is the ultimate means of studying the origin of ultra-high-energy cosmic rays, in which the large radio detection array giant radio array for neutrino detection (GRAND) project aims to use to decipher this century-old problem. The GRANDProto35 compact array is a microform of 35 radio prototype detectors for the GRAND experiment, which verifies the reliability of GRAND performance through operation, and data analysis of the prototype detectors. As radio detectors are a novel development in recent years, and their indexes need to be verified by tra-ditional detectors, the GRAND Cooperation Group designed and constructed the GRANDProto35 coincidence array composed of radio detectors and scintillation detec-tors. This study simulated the changes in detection effi-ciency, effective area, and event rate of cosmic rays with zenith angle based on this coincidence array. The study found that the 1017 eV energy region is sensitive to GRANDProto35 detection. When the energy exceeded 1017 eV, the array detection efficiency could reach more than 95％and the effective area was up to～2 × 106 m2. A simulation study on cosmic ray events with large zenith angles showed that the event rate detected by the array decreased significantly with increasing zenith angle, and the event rate of cosmic rays was approximately 0.1 per day for a zenith angle of 75°. This serves as the background pollution rate for neutrino observation caused by large-angle cosmic-ray events, providing an important reference for further experiments. The study results will be verified after the joint operation of the coincidence array.