Abstract: In this paper, carboxyl-containing acrylate copolymer hydrosol was synthesized by solution polymerization and the film was thermoset-crosslinked with melamine formaldehyde resin HMMM crosslinking agent. The effects of crosslinking agent on the film properties were investigated through a series of tests. The crosslinking degree, damping properties and heat resistance were analysized by IR, DMA and thermal expansion apparatus respectively. The experimental results show that the dense network structure is formed during the thermoset-crosslinking reaction. The water resistance, chemical resistance and mechanical properties are all better. The carboxyl group is involved in the curing reaction by infrared analysis. DMA tests and thermal expansion analysis show the damping properties and heat resistance are both better.