[Objectives]  Leeks are a popular vegetable and Bradysia odoriphaga has recently become an important root pest of leek crops. Long-term excessive application of highly toxic chemical pesticides has seriously affected peoples’ health and caused environmental pollution. Evaluating potential biological control agents for B. odoriphaga is therefore both timely and important. Stratiolaelaps Scimitus is a predator with the same habitat as B. odoriphaga. A predator's functional response is a key factor in the population dynamics of predation and predation systems. Although previous studies have shown that S. scimitus prefers feeding on larvae of B. odoriphaga, there is currently no published information on the predatory functional response of S. scimitus to B. odoriphaga. [Methods]  The functional response of S. scimitus to B. odoriphaga was studied in a laboratory. [Results]  The function responses of S. scimitus to B. odoriphaga approximated the Holling II equation. There was intraspecies interference among S. scimitus and its search efficiency decreased as prey density increased, which suggests that B. odoriphaga has an obvious interference effect on S. scimitus. [Conclusion]  S. scimitus is a natural predator of B. odoriphaga that has potential as a biological control for this pest.