Abstract: A rosin-based anionic surfactant with azobenzene group named sodium 4-maleopimaric acid ethyl ester azophenol(E-MPA-AZO-Na) was synthesized through D-A addition, amidation, diazotization, coupling reaction, esterification, and acid-base neutralization using rosin as raw material. Its structure was characterized by FT-IR and NMR. The surface activities and foam properties were investigated by surface tension method, Nile red(NR) fluorescence probe method and polarizing microscope. The results showed that the critical micelles concentration(C_cmc) of surfactant E-MPA-AZO-Na was only 0.035 mmol/L, the surface tension at the C_cmc(λ_cmc) was 47.11 mN/m, and the minimum area per molecule(a_min) was 1.35 nm², which meant that E-MPA-AZO-Na possesses excellent surface activities. Stable foams could be stabilized when the concentrations of E-MPA-AZO-Na were 0.375, 0.750 and 1.500 mmol/L. Better foaming abilities, smaller foam size and more stable foam emerged with increasing E-MPA-AZO-Na concentration. What's more, the half-life time of the foams formed at 0.375, 0.750 and 1.500 mmol/L were 1 292, 1 770 and 2 534 min, respectively, indicated that E-MPA-Azo-Na possessed outstanding foam stability.