Abstract: During storage self-condensation is easy to occur for phenolic resol resin with low stability. In this article,two ways were used to modify the phenolic resol resins.One was to decrease the activation of hydroxymethyl by introduction of allyl chloride,the other was to introduce polyethylene glycoland to synthesize high ortho phenolic resol.The change of functional groups in phenolic resol resins before and after modification was characterized by infrared spectroscopy (FT-IR).The thermal properties and the curing kinetics were characterized by differential scanning calorimety (DSC).The storage properties of the phenolic resol resins were observed by viscosity.The results indicated that two modified phenolic resol resins were successfully prepared and the hydroxyl group activation was decreased,while the activation energy was changed little as showed by the curing kinetics,which indicated the increase in storage stability with less effect on curing.The storage period of the phenolic resin after modification by allylation could be increased from 30 d to 108 d.After modification by polyethylene glycol,the storage period also reached 108 d.