Abstract: The paper presents a new type of lightweight composite wall composed by gluing two pieces of bamboo plywood on the surface and a piece of profiled steel sheet in the core, closed the both sides of wall by two pieces of thick bamboo plywood and fixed them with self-tapping screws. Pseudo-static tests on a total of 5 composite walls, observed the change of strain in the steel sheets and bamboo plates at all level loads, acquired the bearing capacity, ductility, dissipative coefficient, and other indictors about aseismic performance, which took thickness of the bamboo plywood, thickness and wave-height of the steel sheet into account factors. The result shows that changes of thickness of bamboo plywood have little effect on the shear strength and stiffness of composite walls, but changes of thickness and wave-height of a profiled steel sheet make very sharp differences to bearing capability and aseismic performances of these walls. Based on the stress-strain curve within elastic range of composite walls, this paper proposes a simplified mechanical model and a calculation method for bearing capacity, and the calculated values of bearing capacity match well with the experimental ones.