Objective: To investigate the expression of long non-coding RNA（lncRNA） prostate cancer associated transcript 4（PCAT4） and its clinical significance in prostate cancer. Methods: Real-time-PCR method was used to determine the relative expre-ssion of PCAT4 in 48 cancer samples and corresponding paracancerous tissues from patients with prostate cancer, as well as prostate cancer cells PC3, 22RV1 and normal myofibroblast stromal cells WPMY-1. The relationship between the expression level of PCAT4 and the clinicopathological characteristics of patients with prostate cancer was analyzed. We detected the effects of PCAT4 on the cell proliferation and migration of prostate cancer cells by RNA interference, CCK-8 assay, and migration experiment. Results: The relative expression levels of PCAT4 in the prostate cancer tissues and adjacent tissues were 6.15±1.58 and 1.77±0.65, respectively （P<0.001）, while the relative expression levels of PCAT4 in the prostate cancer cell line PC3 and 22RV1 were higher than that in WPMY-1. The high expression of PCAT4 in the prostate cancer tissues was found in 30 cases of 48 cases, and 18 cases were low expression. The relative expression level of PCAT4 in prostate cancer tissues was associated with Gleason score and T stage （both P<0.05）, and was not associated with age, tumor size, lymph node metastasis and multiple lesions （all P>0.05）. In addition, the siRNA-mediated knockdown of PCAT4 in PC3 and 22RV1 cell lines significantly decreased the ability of proliferation and migration （all P<0.05）. Conclusion: The relative expression level of PCAT4 was elevated in prostate cancer. PCAT4 may promote the carcinogenesis and development of prostate cancer by affecting the proliferation and migration of prostate cancer cells, which can be used as a potential novel target for the diagnosis and treatment.