Hypoxia-activated prodrugs that specifically target tumortissues were designed by attaching the nitro-aromatic ring carrier molecules that can be degraded in the hypoxic microenvironment of the tumor to the hydroxyamidine group of IDO1 inhibitor compound B and epacadostat. Eleven prodrug compounds were synthesized and their structures were confirmed by 1H NMR and HR-MS. Compounds F-1 and F-6, which had a higher stability and drug release rate, were identified by an in vitro stability assay, nitroreductase reduction assay, MTT assay, and an in vivo tumortissuehypoxia degradation assay, and then evaluated for anti-tumorefficacy in vivo. The results showed that prodrug F-1 inhibited tumorgrowth by 67.41%, which was significantly higher than 42.31% for the starting drug group. It appeared that the inhibition of IDO1 in the tumortissue was different from the overall inhibition of IDO1 in vivo. Animaltreatmentprocedures were carried out with the approval of the Animal Care and Use Committee of the ChineseAcademy of Medical Sciences and Peking Union Medical College.