Abstract: Response surface analysis was used for the liquefaction conditions optimization of peanut shell liquefaction by phenol and concentrated sulfuric acid. Experimental design and data analysis were performed using by Design-Expert 8.0.6 software. A central composite design was used to investigate the effects of four experimental factors, namely ratio of liquid to solid(mass ratio of phenol and peanut shell), liquefier temperature, liquefier time and catalyst amount on residue ratio, amount of combined formaldehyde and free phenol content of liquefaction products. The results showed that the optimum liquefaction conditions were mass ratio of phenol and peanut shell 3.0, 120 ℃, 80 min and catalyst amount 10 g(per 100 g peanut shells). The residue ratio, amount of combined formaldehyde and free phenol content of liquefaction products under the optimum conditions were 34.11%, 0.65 g and 30.25%, which were almost equal to the predictable value and could provide a reference for peanut shell used in wood industry adhesives.