[Objective] The research aimed to determine the accuracy, sensitivity and linearity of sialic acid concentration by high performance liquid chromatog. (HPLC), enzymic and resorcinol methods,and discuss the practical application characteristics of the three methods.[Method] Establishing methods for the determination of sialic acid concentration by HPLC, enzymic and resorcinol methods,and determining the sialic acid concentration in the same biol. products using the three methods.[Result] The linear range of HPLC method was 0.3-2 500.0 μg/mL, and the recovery rate was 98.0%-99.2%, within-day and day-to-day RSD were 0.8%-1.4% and 1.6%-1.8% resp.The linear range of enzymic method was 0.6-20.0 μg/mL, and the recovery rate was 102.0%-106.5%, within-day and day-to-day RSD were 3.5%-4.2% and 4.0%-4.6% resp.The calibration curve of resorcinol method was 39-1250 μg/mL, and the recovery rate was 98.2%-100.2%, Within-day and day-to-day RSD were 2.9%-3.3% and 3.0%-3.5% resp.[Conclusion] There is no significant difference among the three methods in terms of recovery and precision, but HPLC is more simple, convenient, inexpensive, sensitive, and has a wide linear range, which can be widely used for the determination of sialic acid in biol. products.