The application of resol as a crosslinking agent with polyacrylamide has become widespread, but it is not clear for forming mechanisms of extraordinarily high activity of the resol. In this research, the major components of the resol and their mass percentage are investigated by Liquid chromatography-mass spectrograph, the mechanism of forming the components is exploited. The evolution of formaldehyde, phenol, and first formed addition products were quantitatively traced by fitration and high-performance liquid chromatography, furthermore the kinetics of synthesis is studied based on the analyzing results. The results show that the resol is composed of nine compounds and the sum of percentage for each integral area is more than 99%. Ini addition, the constant of overall reaction rate k consists of three values of 5.667 X 10(-5), 7.236 X 10(-5), and 23.05 X 10(-5) s(-1), which means that the reaction can be separated to three stages of hydroxymethylphenol (HMP) producing stage, dihydroxymethylphenol (DHMP) and trihydroxymethylphenol (THMP) producing stage and condensation stage. (c) 2007 Wiley Periodicals, Inc.