Multi-polymer blending with complementary properties is a direct and efficient way to obtain materials with improved properties. However, it is difficult to mix between different types of polymers. Block and graft polymers are commonly used incompatible polymer mixed solubilizers, exhibiting interfacial activity at the interface, but their interfacial properties are difficult to predict. Based on Monte Carlo computer simulation technology, this paper studied the effects of molecular chain length and concentration of the ternary polymer blend system on the interface of the system. The simulation result showed that the interface of the ternary block or graft polymer blend interface exhibits no stretching in the direction perpendicular to the interface direction, and the graft polymer branch exhibits interface stretch in the direction perpendicular to the interface direction. The thickness of the interface increases with the increasement of the block or graft polymer. This study on the interfacial properties of ternary polymer blend system not only contributes to the development of new polymer materials, but also enhances the theoretical understanding of the interfacial properties of multi-polymer blend system and the intrinsic link of copolymer solubilizers.