Abstract: Spherical micelles self-assembled from branched alternating copolymer poly(styrene-alt-maleic anhydride) (BPSMA) in selective solvent DMF-H2O was utilized as novel particulate emulsifiers to stabilize white oil-water interface. The influence of both micelle concentration and pH in micelle solution on the emulsifying performance of micelles was investigated. The self-assembly of BPSMA in solution was traced by UV-Vis and the properties of the formed BPSMA micelles were characterized by particle size and Zeta potential analyzer and Transmission Electron Microscopy (TEM). The morphology of emulsion droplets was characterized by optical microscope, the morphologies of micelles at oil-water interface was obserbed by Scanning Electron Microscope (SEM). BPSMA micelles exhibit excellent emulsifying efficiency, and the emulsions stabilized by BPSMA micelles shows distinguish long-term stability, even with very low micelle mass concentration of 0.25—1.00 mg/mL. The emulsions are pH-dependent. Stable emulsions could be obtained with micelles adsorbing at the interface as pH≤6, while most oil separated out as pH>6. Additionally, BPSMA micelles also can stabilize dicaprylyl carbonate, propylheptyl caprylate, silicone oil, isooctyl palmitate and sensoft oil, etc.