Objective This study was to develop a HPLC-MS/MS method for determination of etomidate and etomidate acid in blood samples.Methods The blood samples were deproteinized with acetonitrile and supernatant was achieved by shake,sonication,centrifuge and filtration using 0.22 μm membrane.Then,supernatant was performed on an analytical column Poroshell 120 EC-C18(150 mm×3.0 mm,2.7 μm)and flowed with 0.1%formic acid(mobile phase A)and acetonitrile(mobile phase B).The gradient elution at a flow rate of 0.8 mL/min was determined using an electrospray ionization source in positive ion mode and multiple reaction monitoring mode.Results The linearities of etomidate and etomidate acid in blood samples were good within the corresponding range and the correlation coefficients(r)were over 0.9988.The limit of detection(LOD)of etomidate and etomidate acid were 19.94 and 40.25 ng/mL,and the limit of quantitation(LOQ)of them were 50 and 100 ng/mL,respectively.Moreover,matrix effects were ranged from 1.47%to 10.34%and recoveries ranged from 82.81%to 90.07%.The detection of a positive case using our method was successfully determined to be 1 138.89 and 3 126.41 ng/mL for the contents of etomidate and etomidate acid,respectively.Conclusion Our study has further confirmed that this method with simple pretreatment,little sample usage and wide linear range,can be successfully applied to the detection of forensic sciences on etomidate and etomidate acid.