To explore potential indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors, we designed a series of compounds incorporating urea and 1,2,3-triazole structures. IDO1 enzymatic activity experiments with the synthesized compounds were used to verify their molecular-level activity; for instance, the half maximal inhibitory concentration value of compound 3c was 0.07 μM. Our research has yielded a series of novel IDO1 inhibitors which may be beneficial in the development of drugs targeting IDO1 for cancer treatment.