Urea formaldehyde resin is an end-stage thermosetting resin in which urea and formaldehyde are polycondensated into an initial urea formaldehyde resin under the action of alkaline or acidic catalyst, and then an insoluble and non-fusible resin is formed under the action of curing agent or additives. Urea formaldehyde resin has the characteristics of colorless curing adhesive layer, good operation performance, low cost, good bonding performance and water resistance. Its use in the field of wood bonding is increasing. The cured urea formaldehyde resin is lighter in color than phenolic resin, translucent, resistant to weak acid and alkali, good insulation, excellent wear resistance and low price. However, urea formaldehyde resin is easy to decompose in case of strong acid and alkali, and its weather resistance is poor. There is a problem of formaldehyde emission in the manufacturing and use of wood-based panels produced by urea formaldehyde resin, so it must be modified. At present, urea formaldehyde resin is the largest adhesive used in wood industry, especially in the manufacture of various wood-based panels in wood processing industry, urea formaldehyde resin and its modified products account for about 90% of the total amount of adhesive. In this paper, the development and application of colloidal theory in urea formaldehyde resin are introduced, and the significance and Prospect of this theory are prospected.