As well known, the formaldehyde is emitted from wood-based composite panels bonded with urea-formaldehyde (UF) resins by its hydrolysis, reversible reactions to the synthesis reactions of UF resin. In order to reduce the formaldehyde emission, one of the most promising ways is to reduce F/U mole ratio for UF resin synthesis. However, lowering F/U mole ratio results in low emission at the expense of the loss of resin reactivity, adhesion performance and some mechanical properties. One of the main reason of poor adhesion of low mole ratio UF resins is the formation of crystalline structures in liquid and cured UF resins, which hinders the building of three dimensional networks in the resins. This presentation introduces a new innovative method of modifying UF resins with nanoclay to prevent the formation of crystalline structures, which simultaneously improves the formaldehyde emission and adhesion. These results suggest that the modification of UF resin adhesives with nanoclay improve their cohesion strength.