A kit for rapidly and quantitatively detecting antimicrobial susceptibility, comprising a reagent capable of directly detecting bacterial ATP. After adding the reagent at once, lysis of bacteria and release and detection of ATP can be achieved in one step, and experimental results for antimicrobial susceptibility can be obtained in 2 hours. Any microplate type luminescence detector can be used, and an automatic sample injection system is not required. The operation for adding samples is done in one step, and there is no need to inject a lysis solution and an ATP-detecting reagent separately. An MIC value can be determined, and whether the bacteria are drug resistant is also reported.