Objective To study the effect of perioperative nutritional support on protein metabolism and immunity in patients underwent liver transplantation. Methods A total of 80 patients who underwent liver transplantation in our hospital from March 2015 to March 2016 were collected retrospectively, and then the 80 patients were divided into control group (n=40) and observation group (n=40) according to the type of perioperative nutritional support. Patients of control group didn’t receive preoperatively nutritional support, and received total parenteral nutrition support before postoperative exhaust, then received enteral nutrition support after anal exhaust. Patients of observation group receive preoperatively nutritional support before surgery, and received parenteral nutrition and enteral nutrition support before postoperative exhaust. The several parameters about nutritional status and immune function were observed on 7 days and 14 days after liver transplantation, and comparison of the 2 group in these parameters was performed. Results On the protein metabolism, the levels of serum transferrin, prealbumin, and nitrogen balance on 14 days after liver transplantation were higher than those of other time points (before liver transplantation and 7 days after liver transplantation),P<0.05, both in control group and observation group. There was no significant difference in the levels of serum transferrin, prealbumin, and value of nitrogen balance between the 2 groups before liver transplantation (P>0.05). But on 7 days and 14 days after liver transplantation, the levels of serum transferrin, prealbumin, and value of nitrogen balance of the observation group were higher than those of control group (P<0.05). On the immunity, the total number of lymphocytes, value of IgG and CD4/CD8 on 14 days after liver transplantation, were superior to other time points (before liver transplantation and 7 days after liver transplantation),P<0.05, both in control group and observation group. There was no significant difference in the total number of lymphocytes, value of IgG and CD4/CD8 between the 2 groups before liver transplantation (P>0.05). But on 7 days and 14 days after liver transplantation, the levels of the total number of lymphocytes, value of IgG and CD4/CD8 in the observation group were superior to those of control group (P<0.05). Conclusion Perioperative nutritional support can improve the nutritional status and immune function in patients underwent liver transplantation.