Abstract: Objective : To evaluate the effect of prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) on primary clinical tumor-node-metastasis (TNM) staging and treatment strategies for intermediate-and high-risk prostate cancers. Methods: The clinical and imaging data of 63 patients with intermediate-and high-risk prostate cancers at Chongqing University Cancer Hospital between October 2019 and November 2021 were retrospectively evaluated. The differences between PSMA PET/CT and conventional imaging in lesion detection rate and initial prostate cancer TNM stage were analyzed, and the effect of PSMA PET/CT on treatment strategies was assessed. Results: The detection rates of lymph node and bone metastases using PSMA PET/CT were 23.81% (15/63) and 52.38% (33/63), respectively, 3.17% (2/63) and 25.40% (16/63) more than those determined using traditional imaging, and the differences were significant (all P<0.001). The TNM stage changed for 53.97% (34/63) patients after PSMA PET/CT examination, and the N and M stages were upregulated (all P<0.05). A total of 22.22% (14/63) patients had changes in the treatment plan. Conclusions: The initial N and M stages of intermediate-and high-risk prostate cancers had been upregulated after PSMA PET/CT examination, which led to a change in clinical treatment strategies for more than 20% of patients. PSMA PET/CT may potentially be the first-line imaging modality to accurately assess the whole-body tumor burden in patients with intermediate-and high-risk prostate cancers.