Objective?To investigate the effect of caffeic acid tablets combined with recombinant human interleukin-11 (rhIL-11) on the prevention of thrombocytopenia after chemotherapy for leukemia, and to provide clinical reference. Methods?A total of 120 cases of leukemia patients in Zhaoqing First People’s Hospital from December 2018 to June 2020 were selected and randomly divided into observation group 1, observation group 2 and control group by random number table, with 40 cases in each group. Observation group 1 and observation group 2 were treated with caffeic acid tablets combined with rhIL-11 at different doses, while the control group was treated with rhIL-11. The incidence of thrombocytopenia in the three groups after treatment was compared, and the levels of platelets, white blood cells, granulocytes and hemoglobin in the three groups were observed before and after treatment. The incidence of adverse reactions was compared among the three groups. Results?The incidence of thrombocytopenia in observation group 1 and observation group 2 was significantly lower than that in control group (P ＜ 0.05). Platelet count, white blood cell count and granulocyte count in 3 groups were lower than before 7 and 14 days after treatment, but observation group 1 and observation group 2 were significantly higher than control group, observation group 1 was significantly higher than observation group 2 (P ＜0.05). There was no significant difference in the incidence of adverse reactions among 3 groups (P ＞ 0.05). Conclusion?Compared with rhIL-11 alone, using different doses of caffeic acid tablets combined with rhIL-11 can more effectively prevent thrombocytopenia, and the effect within the scope of rational drug use is positively correlated with the dose of caffeic acid.