Polyaldehyde resin with a relative density of 1.14 to 1.19. The melting point is 88~108 degrees centigrade. The vitrification temperature is T50 ~ 75 C. Soluble in ethanol, isopropanol and toluene, ethyl acetate, acetone, butanone and cyclohexanone, such as chloroform, slightly soluble in cyclohexane, insoluble in petroleum ether and water. It has strong adhesive force, high gloss, high hardness, good weatherability and chemical resistance. It has good compatibility with epoxy resin, phenolic resin, amino resin, chlorinated polypropylene, polyamide, chlorinated rubber, rosin resin and petroleum resin, and is non-toxic.