〔Abstract〕 Objective To provide an animal model for studying the effect of TDO2 on the function of macrophages on the occurrence and development of diseases by constructing macrophage-specific tryptophan, 2, 3-dioxygenase(TDO2) gene knockout mice. Methods TDO2flox/floxLyz2-iCre+mice were constructed based on Cre/LoxP system. The genotypes of mice were identified by PCR amplification and agarose gel electrophoresis.Western blot and immunofluorescence were used to verify the effect of TDO2 knockdown in mouse macrophages. The spontaneous lesions in major tissues and organ were observed by HE stainings. Results The results of genotype identification showed that the mice with only one band at 407 bp or 408 bp for the flox amplification product and one band at 543 bp for the Cre amplification product were TDO2flox/floxLyz2-iCre+mice. Western blot results showed that TDO2 expression in bone marrow-derived macrophages(BMDMs) of TDO2flox/floxLyz2-iCre+mice decreased compared with TDO2flox/floxmice(P<0.01). Immunofluorescence results showed that TDO2 expression in peritoneal macrophages and BMDMs of TDO2flox/floxLyz2-iCre+mice decreased compared with TDO2flox/floxmice. HE staining showed no significant differences in cell morphology in the liver, brain, kidney and spleen tissues of TDO2flox/floxLyz2-iCre+mice compared to TDO2flox/floxmice. Conclusion TDO2flox/floxLyz2-iCre+mice is successfully constructed, providing a more precise experimental animal model for subsequent in-depth study of the role and mechanism of TDO2-regulated macrophage activation in disease.