The present study examined the pharmacokinetics of IMM‐H012 in rat plasma, utilizing ultra‐performance liquid chromatography‐tandem mass spectrometry (UPLC‐MS/MS). Internal standard cilostazol was employed, and plasma samples were processed using acetonitrile precipitation. A mobile phase (acetonitrile–0.1% formic acid in water) with gradient elution was used to achieve chromatographic separation using a UPLC BEH C18 column. In multiple reaction monitoring mode, electrospray ionization MS/MS was utilized in positive ionization mode. Based on findings, the lower limit of quantification was 2 ng/mL, and the linearity of IMM‐H012 in rat plasma was found to be acceptable within the range of 2–2000 ng/mL (R2 > 0.995). The intra‐day and inter‐day precision relative standard deviation was less than 14% of IMM‐H012 in rat plasma. The matrix effect was within the range of 102%–107%, and the accuracy ranged from 92% to 113%. Pharmacokinetics of IMM‐H012 in rats after oral administration were successfully studied using UPLC‐MS/MS.