To explore the factors that affect the generation of furfural inhibitor during the process, corn stover was pretreated using diluted sulfuric acid. The correlation between pretreatment conditions and reducing sugar and furfural was analysed by partial correlation. The analysis showed that the main factor affecting furfural generation was the concentration of the sulfuric acid. There was a positive correlation between the concentration of furfural and sulfuric acid. Pretreatment temperature and time were associated with the furfural concentration significantly; however the solid〖CD*2〗liquid ratio was not associated with the generation of furfural. The results showed that the optimal results were achieved by using 1% sulfuric acid to pretreat the corn stover at 120 ℃ for 90 minutes and ratio of solid to liquid 1∶10, as results, the furfural concentration was measured as 0.99 mg/mL with reducing sugar at 27.6 mg/mL.