The conformation of amphiphilic branch chain in a new type of copolymer surfactants on interface was studied. The results of laser light scattering demonstrated that the branch chain can only lie on the air/water interface. By means of XPS measurement with variable angles, the molecular conformations in different thickness of the copolymer layer were obtained. Depending on the chemical nature of the copolymer surfactants, the oxyethylene segments of the branch chains will have loop-train, train, or loop molecule conformations on the surface.