The invention relates to a light concrete cast-in-place robot, the cast-in-place robot comprises a vehicle body, a motion system, a discharging system, a vibrating system, a plastering system and a control system electrically connected with the motion system, the discharging system, the vibrating system and the plastering system, the motion system is arranged at the bottom of the vehicle body, thedischarging system, the vibrating system and the plastering system are all arranged on the vehicle body, the discharging system comprises a discharging cylinder internally provided with a concrete channel, the bottom of the discharging cylinder is provided with a concrete discharging port with an opening towards the rear portion of the vehicle body, the vibrating system comprises a vibrating rodwhich can ascend and descend and is located on the rear portion of the vehicle body, the plastering system comprises a plastering device with multiple degrees of freedom, and the plastering device islocated on one side of the vehicle body. Compared with the prior art, the light concrete cast-in-place robot has the advantages that concrete discharging, vibrating and plastering can be conducted atthe same time, light weight and flexibility are achieved, traditional manual labor is replaced, and the construction mechanization degree is improved.