A combined greenhouse has a foundation bed, an outer wall assembly, a temperature control assembly, a roof and a plant bed. The foundation bed has multiple stands and a reinforcing device. The outer wall assembly is mounted on the foundation bed and has four walls and an outer frame. Each wall has a base frame and a transparent device. The outer frame is mounted outside the wall that is mounted on the front stand of the foundation bed. The temperature control assembly is mounted in the foundation bed and has a ventilating device, a water-wall device and an air-sucking device. The roof is mounted on the outer wall assembly and has multiple roof mounts. The plant bed is mounted on the reinforcing device and each has two end frames, at least one linking frame, a baseboard, a plant net and multiple resisting boards.
