The invention discloses a composite type wall greening device and method. The composite type wall greening device comprises a backing plate, a planting blanket and a planting box. The backing plate is installed on a to-be-greened wall and the planting blanket is spread on the backing plate. The planting box comprises a fixing plate, two bag bodies and water storage partition plates. Hanging buckles are arranged on the upper portion of the fixing plate. Hanging holes are formed in the lower portion of the fixing plate. Fixing holes are formed in the side edge of the fixing plate. The bag bodies are installed on the fixing plate in the horizontal direction in a spaced mode. The parts where the fixing plate makes contact with the bag bodies are hollow. The water storage partition plates are connected to the lower edges of the hollow positions of the fixing plate and are protruding out of the fixing plate. According to the composite type wall greening device and method, a plurality of planting boxes can be rapidly assembled and connected up and down, and the installation difficulty is greatly lowered; plant roots can beneficially root in the planting blanket through the structure of the planting box, and plant growth and survival are facilitated; and meanwhile, the planting box is made of a plastic material, so that the problems that traditional planting blanket bag bodies are prone to getting mildew and becoming dirty, and moisture evaporating and dissipation are too rapid are effectively solved.