Resol type of phenolic resin was cured investigating the effect of curing kinetics on the cross-link density and mechanical property. Its conversion and cross-link density increased with isocuring temperature and time. It had almost the same value of activation energy for curing as general epoxy resins. The resol resin showed the increase in tensile strength, tensile modulus and toughness with isocuring time. It showed the decrease in elongation at break with isocuring time when cured at a fixed temperature. The resol resin cured at 210℃ had lower or equal mechanical properties with those resins cured at 150℃ and 180℃ because water vapor was generated as a by-product.