Abstract: The phenolic resin synthesized from phenol and formaldehyde in the presence of a tertiary amine catalyst was chemically modified with a small amount of aniline derivative to produce a higher molecular weight,modified phenolic resin.The resulting resin was used as the curing agent of epoxy resin to produce the epoxide woven glass fabric laminated sheet.The insulation resistance after immersion in water of the laminated sheet is greater than 10¹¹Ω,and other properties are similar to those of EP GC201(IEC 893-3-2).Molecular weight distribution and structural feature of the modified phenolic resin were studied by means of gel permeation chromatography(GPC),infrared spectroscopy(IR)and proton magnetic resonance(¹H-NMR)analytical techniques.