A series of reactive latexes which contains acetoacetate groups was synthesized by seeded semicontinuous emulsion polymerization. The size and morphology of the latex particles were investigated by TEM analysis. The results showed that the latex particles dispersed narrowly and the diameter of the latex particles was about 80 nm. The crosslinking reaction of acetoacetate groups with diamine was investigated by FTIR. The crosslinking reaction could take place completely in 48 hs at ambient. The effects of crosslinking agent AAEM on the films` Tg, water absorbtion, crosslink density and machanical properties were investigaed. The results showed that the latex films balance property had been developed via the crosslinking reaction at ambient. The excellent waterborne coatings for wood were prepared.