Abstract: Objective To investigate the effect of ω-3 fatty acids (Fat Emu Ision Injection) on factors in arterial blood and its mechanism. Methods Ninety SD rats were randomly divided into normal control group, heat stroke model group, heat stroke Omega-3 fish oil Fat Emulsion Injection treatment group, with 30 rats in each group. The rats were placed in the constant temperature box at 40℃ and 60% relative humidity for one hour to established heatstroke model. The Omega-3 fish oil fat emulsion injection treatment group received tail vein injection of Omega-3 fish oil Fat Emulsion 1.67 ml/(kg·d) after molding. Normal control group and model group received the same dosage of normal saline of tail vein injection. One time per day for both group and continued for 3 days. The body temperature, heart rate, and mean arterial pressure (MAP) were recorded separately for 3 groups after 12 hours, 24 hours and 48 hours; At three different time point, abdominal aorta blood in 10 rats from each group w was drawn to prepare serum, and the levels of lipopolysaccharide (LPS), nuclear factor kappa B (NF-kappa B) and P53 were tested by ELISA. Results Compared with normal control group, the heatstroke body temperature, heart rate, LPS, NF-B, P53 at three time points in model group were significantly increased (P<0.05), MAP decreased obviously (P<0.05); compared with the model group, the above indexes in the Omega-3 fish oil fat emulsion injection treatment group at the three time points was improved obviously (P<0.05). Conclusion Omega-3 fish oil fat emulsion injection can significantly improve the expression level of LPS, NF-kappa B and P53 in heat stroke rats, suggesting that it can inhibit LPS entry into blood and may affect vascular endothelial cells.