Provided are uses of the combination of a μ opioid receptor (MOR) agonist and a κ opioid receptor (KOR) agonist in the preparation of drugs for relieving and/or treating pain. The MOR agonist is selected from the compound represented in formula (I), or a tautomer, mesomer, racemate, enantiomer or diastereomer thereof, or a mixture thereof, or a pharmaceutically acceptable salt thereof. Also provided is a pharmaceutical composition containing the MOR agonist and the KOR agonist.