The invention provides an on-line dynamic and static mixer which is provided with a barrel; a liquid inlet is formed in the front end of the barrel, and a mixing outlet is formed in the rear end of the barrel; an injection conduit is designed to extend into the barrel to be close to the front end from the radial side surface of the barrel, and the outer end of the injection conduit is provided with a medium inlet; a distributor is provided with a plurality of guide pipes arranged in a radial shape, the outer ends of the guide pipes are closed, the inner ends of the guide pipes are communicatedwith the injection conduit, and a plurality of spray holes are formed in the side wall of each guide pipe; a mixing internal part is arranged in the barrel at the downstream of the distributor; stirring blades are fixed in the barrel at the downstream of the mixing internal part, and a rotating shaft of the stirring blades is designed to extend out of the barrel along the radial direction and isconnected with a motor; the flow velocity detector is installed at the position, close to a liquid flow inlet, in the barrel and is in signal connection with the motor. The distributor, the mixing internal part and the stirring blades are adopted, so that a static mixer and a dynamic mixer are integrated, and the mixing efficiency is improved.