The invention discloses a high-efficiency mixing device and process for environment-friendly concrete. The device comprises a mixer body and a bottom plate, wherein the top surface of the mixer body is fixedly connected with a cement bin; a stirring cavity is formed in the lower part of the interior of the mixer body; a discharging cavity is formed in the upper position of the interior of the mixer body, the discharging cavity communicates with the stirring cavity, and the cement bin communicates with the discharging cavity; and one side of the mixer body is fixedly connected with a water tank and a water pump. According to the high-efficiency mixing device and process, when water is injected, the water pump inputs the water into a water injection assembly, the water injection assembly is provided with a plurality of hemispherical water injection heads, under the action of a third motor, the hemispherical water injection heads rotate, water flow is scattered into the mixer body, at the moment, cement flour falls, the water flow is in contact with the cement flour, the cement flour is evenly wetted, then the cement flour falls into the stirring cavity, and meanwhile, part of water flow is sprayed into the stirring cavity to complete water injection work, so that, on one hand, the water injection uniformity is guaranteed through water injection, and on the other hand, the cement flour can be uniformly wetted, and the situation that part of the cement flour is wetted and condensed after being in contact with the water flow is avoided.