Objective To compare influences of enteral nutrition (EN) and parenteral nutrition (PN) on the inflammatory factors and immune functions in patients with systemic inflammatory response syndrome. Methods Totally 85 patients who were treated in the First Hospital of Shanxi Medical University, Shanxi Province People's Hospital, and Taiyuan Central Hospital from April, 2006 to April, 2010 were enrolled in this study and divided into EN group (n = 49) and PN group (n = 36) according to nutrition support modes. The changes of inflammatory factors and immune functions after nutritional supports were recorded and compared between these two groups. Results The weight, arm circumference, skin fold thickness of brachial triceps, total protein, and serum albumin were significantly improved on the 7th and 14th day after nutrition supports in both two groups compared with the baseline levels (all P ＜ 0.05). On the 14th day after nutritional support, the levels of total protein and serum albumin were significantly higher in EN group than in PN group. On the 7th and 14th day, the levels of tumor necrosis factor-α, Interleukin (IL)-8, and IL-1β in EN group were significantly lower than those in PN group and baseline levels (all P ＜ 0. 05). The blood CD4/CD8 and IgG in EN group were significantly increased compared with the baseline levels and those in PN group (both P ＜0. 05). Conclusions Both PN and EN can effectively improve the nutritional status of patients with SIRS. EN has superior effectiveness in EN group than in PN group in terms of improving nutritional status, ameliorating immune function, and reducing the release of inflammatory factors.