The formation regularity of the furfurals and main influencing factors during the dilute acid hydrolysis of corn stalks were studied. The results showed that the conversion reaction of hexose into hydroxymethyl furfural was the primary cause of forming the furfurals, and the efficiency of pentose transforming into furfural was lower. The concentration of reducing sugar was the largest factor which affected the concentration of the furfurals in the hydrolysate, and the concentration of the furfurals significantly correlated with the concentration of reducting sugar in test series. Due to the distinct influence of hydrolysis time on the concentration of the furfurals, the concentration of the furfurals was increased with the increase of hydrolysis time. Moreover, within the concentration range of 0.5%-2.0% of the diluted sulfuric acid, it could improve efficiently the conversion of hexose to hydroxymethyl furfural. Under the experimental conditions, the hydrolysis temperature and solid content had no obvious influence on the formation of the furfurals.