Abstract: In the process of getting succinic acid from by corn straw fermentation, furfural, 5hydroxymethylfurfural, 4Hydroxybenzaldehyde and syringaldehyde always appears at pretreatment stage. This paper established an optimum method by high performance liquid chromatography to analyze these four inhibitors. Results showed that inhibitors were wellseparated under the optimized mobile phase (30%methanol- 70% ultrapure water) with a flow rate of 08mL/min on the YMCTriart C18 column. The Standard curves of four inhibitors indicated that the concentration of all inhibitors was range of 0001-1000g/L, the linear correlation coefficients were above 0999. The concentration of these inhibitors produced in corn stover pretrearment was measured by using the methods and the result showed that, the concentration of inhibitors produced in the processes of pretreatment of dilute acid and pretreatment of hydrothermal was same.