Objective To explore the effect of high-fat diet on arachidonic acid metabolism in prostate and seminal vesicle of SD male rats. Methods Twenty four 45 day old SD male rats were selected and divided into control group, obesity group and conversion group, with 8 rats in each group. The control group was fed with normal diet, the obese group was fed with 45% high-fat diet, and the conversion group was fed with high-fat diet for 2 months and then converted to normal diet. The three groups were fed with high-fat diet for 3 months, and determine the concentration of phospholipid (PL), secretory phospholipase A2 (sPLA2), arachidonic acid (AA), 5 lipoxygenase (5-LOX), cyclooxygenase (COX)1, COX2, leukotriene B4(LTB4), prostaglandin (PG)E1, PGF 2α, Interleukin (IL)1, IL-6, tumor necrosis factor α(TNF- α), testosterone (T) and estrogen (E2). Analyzed the difference of each index among the control group, obesity group and conversion group,. Results The levels of LTB4, IL-6 and TNF-α in prostate obesity group and transition group were significantly higher than those in control group (P＜0.05), and the levels of E2 in seminal vesicle gland obesity group and transition group were significantly higher than those in control group (P＜0.05). In prostate, body weight was positively correlated with AA, all indexes of AA metabolic network were positively correlated, and PGE1 was negatively correlated with IL-6 (P＜0.05). In seminal vesicle gland, body weight was positively correlated with COX1, 5-LOX and E2, except COX2 was negatively correlated with PL and COX1, other AA metabolic network indicators were positively correlated (P＜0.05). Conclusion High-fat diet can affect the AA metabolism of SD male rats, and has a clear incremental effect on the prostate gland, affecting the functional state of the prostate, and the ebb and flow trend of COX1, COX2 and 5-LOX in the seminal vesicles