Provided are a substituted oxadiazole chemical compound and composition containing said chemical compound and use thereof; said substituted oxadiazole chemical compound is the oxadiazole chemical compound as represented by formula (I), or its crystalline form, pharmaceutically acceptable salt, prodrug, stereoisomer, hydrate, or solvent compound. The disclosed substituted oxadiazole chemical compound and composition containing said chemical compound are capable of inhibiting indoleamine 2, 3-dioxygenase; it also has better pharmacokinetic parameter attributes and is capable of improving the drug concentration of the chemical compound in an animal body, thus improving the therapeutic efficacy and safety of the drug.