Omega‐3‐acid ethyl acetate 90 capsules (containing 465 mg of eicosapentaenoic acid and 375 mg docosahexaenoic acid) is composed of highly purified omega‐3 polyunsaturated fatty acid (PUFA) ethyl esters, whose lipid‐lowering effect for severe hypertriglyceridemia (HTG) treatment is unclear. This study aimed to evaluate the efficacy and safety of omega‐3‐acid ethyl acetate 90 capsules in patients with severe HTG. In this randomized, double‐blind, placebo‐controlled, multicenter study, 239 patients with severe HTG were enrolled and randomized (1:1) into omega‐3 group (N = 122) and placebo group (N = 117) to receive 12‐week corresponding treatments. Lipid‐related indexes were obtained at treatment initiation (W0), 4 weeks (W4), W8, and W12 after treatment. Adverse events and adverse drug reactions were recorded. Triacylglycerols (TAG), total cholesterol (TC), non‐high‐density lipoprotein cholesterol (non‐HDL‐C), very‐low‐density lipoprotein cholesterol (VLDL‐C), and apolipoprotein C‐III (Apo C‐III) at W4, W8, and W12 were decreased in the omega‐3 group versus the placebo group (all p < 0.05). Moreover, the percentage changes of TAG, TC, non‐HDL‐C, and VLDL‐C from W0 to W4, W8, and W12, and the percentage change of Apo C‐III from W0 to W4 and W8, were more obvious in the omega‐3 group compared with the placebo group (all p < 0.05). However, no difference was observed in the percentage changes of HDL‐C, low‐density lipoprotein cholesterol (LDL‐C), and LDL‐C/HDL‐C ratio during follow‐up between groups (all p > 0.05). Additionally, there was no discrepancy in adverse events and adverse drug reactions between groups (all p > 0.05). Omega‐3‐acid ethyl acetate 90 capsules exhibit satisfied lipid‐lowering effect with tolerable safety profile in patients with severe HTG.