Prostatic cancer (PCa) is a leading cause of cancer related death in males and is often regarded as a kind of androgen-sensitive cancer. Artesunate (ART), a semi-synthetic derivative of the Chinese herb Artemisia annua, is such an anti-cancer agent. However, the effects and mechanism of ART on PCa cells remains unclear. The study aims to elaborate the mechanism of the involvement of androgen receptor (AR) in anti-prostatic cancer (PCa) of artesunate (ART). PCa cells 22rvl were used in vivo and in vitro, and the viability and apoptosis were conducted using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay, respectively. Ectopic expressions of AR and DNA methyltransferase (DNMT) were detected in cells in overexpression or interference of AR or DNMT3b. ART dose-dependently suppressed tumor growth, inhibited cell viability, enhanced apoptosis, decreased AR expression, and increased the expression and the catalytic activity of DNMT3b in 22rv1 cells either in transplanted mice or in vitro. Furthermore, AR downregulated DNMT3b expression, and overexpression of AR or interference of DNMT3b could reverse ART-induced cytotoxicity and apoptosis in 22rvl cells, whereas overexpression of DNMT3b could not change the effect profiles of ART on the cells. The results indicated that ART suppressed tumor growth of prostatic cancer cells through AR-DNMT3b pathway, underlying ART will allow for the utilization of this Chinese therapeutic agent for the potential treatment of prostate cancer.