Objective  To investigate the prevalence of complete posterior vitreous detachment in rhegmatogenous retinal detachment （RRD） patients and to evaluate the following diagnostic tests： fundus examination， B-scan ultrasound and optical coherence tomography （OCT）. Methods  Thirty patients （30 eyes） with RRD who underwent vitrectomy in Shanghai First People′s Hospital were included in this prospective case-series study. Patients received comprehensive ocular examinations that included fundus examination， B-scan ultrasound and OCT. TA stain （triamcinolone acetonide） was used to assist during the vitrectomy surgery as well as being the gold standard for PVD diagnosis. Data were analyzed using a Kappa test. Results  The rate of detection for the prevalence of complete PVD was as follows： 10.0% by TA stain， 76.7% by B-scan， 36.7% by fundus examination and 13.3% by OCT. Different rates of PVD detection were found by the above examinations and， of these， the difference was most significant between B-scan and observation during surgery. Conclusion  Observation during surgery with the help of TA is comparatively the most persuasive diagnostic method for PVD. Different examination methods can be selected for individual cases.