Waterborne polyurethane-acrylate (WPUA) composite emulsion based on waterborne polyurethane (WPU) was prepared by sequential polymerization with methyl methacrylate (MMA) and butyl acrylate (BA). WPU was synthesized to form seed emulsion dispersion using poly (propylene carbonate) (PPC) diol as soft segment. Polyacrylate (PA) content and MMA/BA mass ratio were varied to investigate the influence on performance properties. The emulsions were characterized by evaluating the particle size, stability, and appearance. The WPUA films were characterized by FT-IR and TGA. The tensile properties, hardness, surface hydrophilicity, and coating adhesion of film were also tested. The incorporation of PA in PPC-based WPU improved the adhesion, pencil hardness, water resistance, and hydrophilicity. With the increase of PA content, the tensile strength increased initially and then decreased, while the elongation at break and toughness decreased. The experimental results indicated good compatibility and synergistic effect between PPC-based WPU and PA, which resulted in a remarkable improvement in thermal properties, adhesion, and pencil hardness.