Objective: To determine the concentration of salicylic acid in healthy male subjects plasma between the aspirin enteric-coated tested preparation and the reference preparation, study the relative bioavailability in vivo, including absorption rate and degree of absorption, and evaluate the bioequivalence of preparations and reference subjects. Methods: The salicylic acid concentration of aspirin effective metabolites in plasma was determined through double random cross test cycle. The samples were chromatographed on a MG PAK-C18 column (150 mm × 2.0 mm, 5.0 μm) using a mobile phase consisting of acetonitrile (0.1% formic acid) and water (0.1% formic acid) (70:30) at the flow rate of 0.3 mL·min-1. The neg. ions of analytes were detected in neg. ionization in selective reaction monitoring mode (SRM). The mass transition pairs of m/z 137.0 → 93.1, m/z 280.0 → 252.0 were used to detect Salicylic acid and Nitrate diazepam (internal standard). Use the DAS 2.1.1 pharmacokinetic software evaluation. Results: None of the two formulations of salicylic acid AUC0-t and Cmax were rejected by bioequivalence hypothesis; AUC0-t 90% confidence interval of the test formulation was 96.6%-112.9% for the reference formulation of the corresponding parameters; Cmax 90% confidence interval of the test formulation was 93.2%-112.2% for the reference formulation of the corresponding parameters, which fells within the equivalent scope. Salicylic acid tmax was tested by nonparametric rank sum test, and differences between the two formulations Tmax was not statistically significant. Conclusion: The two formulations are bioequivalent in vivo.