The invention relates to a light substance processing device, in particular to a light substance processing device for multifunctional construction waste. The light substance processing device comprises a movable bottom frame mechanism, a light substance recycling mechanism, a crushing mechanism and a vibration screening mechanism. According to the device, the construction waste stone material canbe crushed, the crushed construction waste can be subjected to screening treatment, light substances can separated from the construction waste, the light substances and stone residues can be separated, and the light substances can be collected for recycling. The device can move, the light substance recycling mechanism is located above the movable bottom frame mechanism, and the light substance recycling mechanism is connected to the movable bottom frame mechanism through bolts; the vibration screening mechanism is located above the movable bottom frame mechanism, and the vibration screening mechanism is connected to the movable bottom frame mechanism through bolts; and the crushing mechanism is located above the vibration screening mechanism, and the crushing mechanism is in welding connection with the vibration screening mechanism.