Abstract: The present invention discloses an improved structure of a water-jet toothbrush, comprising a hollow base in the front part of the handle to receive and store the replaceable bristle head firmly, a hollow pipe being associated with the rear part of the handle, a source of water being connectable to the rear part of the pipe, a water controller be fixedly mounted to connect the handle and the pipe and to control the flowing of water toward the jet head at the anterior portion of the toothbrush head, a water passage being formed and extended axially from the pipe to the handle and curved inwards within the toothbrush head to connect with the spiral jet head, thereby such curvature direct a strong water stream to clean the residues stored on the tooth crevices and massage the gums effectively.