Purpose: To study the effects of parenteral nutrition (TPN),omega-3 polyunsaturated fatty acid (PUFA), L-arginine (Arg), and glutamine on cellular immunity of patients who have done the liver cancer (LC) surgery. Methods: Seventy-five (75) LC patients were randomly divided into 5 groups (A - E; 15 cases each), group A, B, C, D and E, in which patients were treated with TPN, TPN + fish oil, TPN + Arg, TPN + glutamine, and TPN + omega-3 PUFA + Arg + glutamine, respectively. Before and after surgery, CD3 +, CD4 + and CD8 + were measured by antibody-sensitized erythrocyte rosette test, and IL-6, IL-10 and TNF-a were assayed with double-antibody sandwich enzyme-linked immunoassay (DAS-ELISA). IgA and IgM were measured nephelometrically. Results: The levels of CD3 +, CD4 + and CD8 + in group A showed no obvious change after surgery (p > 0.05). However, CD3 + and CD4 + increased in groups B, C and D, while CD8 + decreased in group E (p < 0.05). IL-6 in group E was lower than that in any of the other four groups (p < 0.05). IL-10 in group A was lower than that in groups B, C and D, but lower than in group E (p < 0.05). The levels of TNF-a in groups B and C were lower than those in group A, but higher than that in group E (p < 0.05) but lower than in group D. IgA in group E was higher than in the other groups (p < 0.05), while IgM level in group E was lower than in groups A, B and C (p < 0.05). Conclusion: Immunosuppressive status and cellular immunity of patients after liver cancer surgery may be improved by a combination therapy of TPN,omega-3 PUFAs, Arg and glutamine.