Anacardic acid, which is commonly seen in plants of Anacardiaceae, is an important composition of cashew, ginkgo leaf and fruit, and it has been suggested in previous research to show antitumor activity. The main aim of the present study was to evaluate the anticancer effects of anacardic acid on cell apoptosis of prostatic cancer and molecular mechanisms of this phenomenon. In this study we found that anacardic acid inhibited cell proliferation, induced apoptosis and caspase-3/9 activities and Bax protein expression of prostatic cancer. Anacardic acid induced the ER stress inducing factors (BiP, CHOP, p-eIF2α), autophagy, LC3, Beclin-1, Atg 7 and DAPK3 protein expression, and suppressed p-Akt and p-mTOR protein expression of prostatic cancer. Si-CHOP was used to inhibit ER stress in prostatic cancer by anacardic acid, which showed that the cell proliferation was increased, apoptosis, and caspase-3/9 activities and Bax protein expression was suppressed, autophagy, LC3, Beclin-1, Atg 7 and DAPK3 protein expression was reduced, and p-Akt and p-mTOR protein expression was promoted. DAPK3 inhibited p-Akt and p-mTOR protein expression, enhanced the anticancer effects of anacardic acid on prostatic cancer through autophagy. For the first time, the present study showed that anacardic acid induces cell apoptosis of prostatic cancer through autophagy by ER stress/DAPK3/Akt signaling pathway.