Objective  To investigate the changes of serum trace elements and immune function in patients with cancer after chemotherapy, and investigate the effect of enteral nutrition on those as well. Methods  Between March and May of 2018, 19 cancer patients, aged 18~70 years, with KPS score equals or more than 60, were enrolled and randomly divided into two groups. One of them with 9 subjects received enteral nutrition intervention during chemotherapy; another group with 10 subjects received chemotherapy only without enteral nutrition intervention. Serum trace elements and peripheral blood lymphocyte subsets were measured before and after chemotherapy. A paired t-test with two-tailed was used to compare two population means by SPSS 18.00,  and the significant difference between two groups was considered when P<0.05. Results  The serum manganese concentration in patients without nutritional intervention after chemotherapy was significantly lower than that before chemotherapy (P=0.004), the serum lead was borderline lower after chemotherapy compared with that before chemotherapy (P=0.057); the serum zinc content in patients with nutritional intervention after chemotherapy was significantly lower than that before chemotherapy, and the NK cell percentage in peripheral blood was borderline decreased in patients with nutritional intervention after chemotherapy compared with that before chemotherapy, while the ratio of CD4+/CD8+ was borderline increased after chemotherapy compared with that before chemotherapy (P=0.057). Conclusion  Chemotherapy and nutrition intervention have certain effects on the concentration of serum trace elements, nutrition intervention has borderline influence on the distribution of peripheral blood T cells, which shows that the proportion of NK cells was borderline decreased after chemotherapy and the ratio of CD4+/CD8+ was borderline increased after chemotherapy. Because the number of cases is limited and the duration of nutrition intervention is short, it is necessary to increase the number of cases and prolong the time of nutrition intervention.