Casein-based emulsion for film former was innovatively prepared via emulsifier-free emulsion polymerization by employing self-made amphiphilic copolymers (A m B n C o ) as the stabilizer. Structure of A m B n C o was confirmed by 1 H NMR spectrometry. Stability of the as-prepared emulsion in different concentrations of A m B n C o was evaluated by measuring their droplet size, microstructure and viscosity. The results indicated that the obtained particles were 40–50nm in size with uniform size distribution, and exhibited obvious core–shell structure. The emulsion containing 1.0wt% of A m B n C o presented superior storage stability.