A reversible addition fragmentation chain transfer (RAFT) agent, 2- (dodecylthiocarbonothioylthio)propanoic acid (RAFT-1), was synthesized and characterized. Equimolar doses of acrylic acid (AA) and n-butyl acrylate were successively polymerized in the presence of RAFT-1 to give an amphiphilic macro RAFT agent (RAFT-2), which had a calculated average degree of polymerization of ten. Core-shell poly (butyl acrylate-co-diacetoneacrylamide) latex was prepared by using RAFT-2 as a reactive surfactant. The latex was narrowly distributed and very stable, which had a solid concentration as high as 45 wt.% and an average diameter of about 50 nm, Latex films were prepared with the core-shell emulsion and small amount of cross-linking agent, adipic dihydrazide. Results showed that cross-linking reaction occurred with the evaporation of water. The resulting cross-linked latex film was tough and transparent.