Abstract： Objective To investigate the efficacy of anlotinib combined with 131I in the treatment of differentiated thyroid cancer(DTC)and its impact on fatigue and erythrocyte parameters.Methods 102 patients diagnosed with DTC in Anyang Cancer Hospital from January 2020 to December 2022 were divided into study group and reference group with 51 cases in each group by random number table method.The reference group was treated with 131I,and the study group was treated with anlotinib combined with 131I.Compare the clinical efficacy of the two groups,as well as fatigue score(CFS),thyroid function[thyroid stimulating hormone(TSH),thyroglobulin(TG),antithyroglobulin antibody(TgAB)],red blood cell parameters[Red blood cell count(RBC),hemoglobin(HBG),erythrocyte sedimentation rate(ESR)],and cellular immune function indicators(NK,CD4+/CD8+,CD4+,CD8+)before and after treatment.Results The total remission rate of the study group(84.31%)was higher than that of the control group(66.67%)(P＜0.05).After treatment,the score of CFS in each dimension of the study group was lower than that of the control group(P＜0.05);the levels of TSH,TG and TgAB in the study group were lower than those in the control group(P＜0.05);RBC,HBG and ESR levels in the study group were higher than those in the reference group(P＜0.05);the levels of NK,CD4+/CD8+,CD4+ and CD8+ in the study group were higher than those in the reference group(P＜0.05).Conclusion Anlotinib combined with 131I has a significant effect on the treatment of DTC,which can reduce the fatigue degree of patients and inhibit the growth of tumor cells.It has no obvious effect on the erythrocyte parameters,which is conducive to the outcome of the disease.