The invention provides a straw-steel system prefabricated wall and a joint connecting method. For a long time, China steel structure is made of connecting steel plates, shaped steel and the like to form basic components, and then transported to a construction site to be installed and connected into an overall structure. Therefore, in the steel structure, connection occupies a very important position, and any steel structures can meet the connection problems. The straw-steel system prefabricated wall comprises a group of straw plates (1), the straw plates are connected to form an L-shaped wallor a T-shaped wall or a cross-shaped wall, C-shaped steel sleeves (2) sleeve the upper and lower faces of the straw plates, the positions of straw plate intersection with inflection points are weldedto the C-shaped steel sleeves through L-shaped steel (14), the positions of straw plate intersection without the inflection points are welded to the C-shaped steel sleeves through strip-shaped steel plates, and plastering layers (15), fireproof layers (16) and waterproof layers (17) are successively arranged on the outer surfaces of the straw plates, the C-shaped steel sleeves, the L-shaped steel,the strip-shaped steel plates and light steel plates. The joint connecting method is used for the prefabricated wall.