〔Abstract〕 Objective To investigate the role of magnetic resonance imaging in the diagnosis of incomplete fracture of knee injury. Methods 39 patients with incomplete fracture of knee injury treated in Zhaoqing Second People's Hospital from January 2019 to January 2020 were selected as the research object. The results of X-ray examination and magnetic resonance imaging of 39 patients were analyzed retrospectively, and the diagnostic results of the two examination methods were compared. Results X-ray examination showed that no incomplete fracture images were detected in all patients; Magnetic resonance imaging showed that thelocation of incomplete fracture in 15 patients was the lateral tibial plateau, 7 patients were the medial tibial plateau, 6 patients were the lateral femoral condyle, 5 patients were the medial femoral condyle, 1 patient was the patella, 5 patients had 2 or more fracture locations, and 3 patients had tibial plateau collapse; The MRI images of all patients were characterized by low signal T1 weighted image, high signal T2 weighted image and proton weighted fat suppression image. Conclusion The application of magnetic resonance examination in the clinical diagnosis of incomplete fracture of knee injury is significantly better than X-ray. It can obtain higher detection accuracy and provide a more comprehensive diagnostic basis for clinical treatment.