Protein and polysaccharide are used as many food function including emulsifying and stabilizing agent. Some food emulsions are in low pH such as sorbet ice cream, soft drink, salad dressing etc. According to our previous study was found that fish gelatin (FG) and sodium alginate (AL) mixture provide the information to be a new food emulsifier including at low pH condition (pH 3.5). In addition the study of interfacial rheology has been interested to interpret the formation and stabilization of food emulsion. Then the objective of this study was to investigate the relationship between emulsifying characteristics and interfacial shear rheology of acidified emulsion which was stabilized by FG and AL mixture, compared with a commercial gum arabic (GA). The mixtures of FG and AL were separately prepared with phosphate-citrate buffer at pH 3.5 and 1 %w/v of total concentration. The ratio of FG:AL was 100:0, 80:20, 50:50, 80:20, and 0:100 by weight. They were mixed at 24±2 oC for 90 minutes and kept at the same temperature for 24 hours to reach equilibrium. The emulsion was prepared by adding 1.5 g of olive oil in 100 ml of mixture and homogenized by high speed homogenizer at 10,000 rpm for 10 min at 24±2 oC. The emulsion stabilized with 20:80 showed the best stability after 14 days. The result could be supported by low interfacial tension, high bulk viscosity, and electrostatic repulsion (minus value of electrophoretic mobility). For interfacial shear rheology (storage modulus, G' and loss modulus, G''), G' of 20:80 seem wider liner viscoelastic region which mean more resistance to fracture at interface. While the magnitude of G' and different value of G' and G'' were not difference. In addition, the interfacial shear viscosity of 20:80 also showed high resistance to flow at low shear rate (0.001 - 0.1 s-1). Keywords: Fish gelatin, Sodium alginate, Emulsion, Interfacial shear rheology