Concrete mixing main machine

The utility model relates to a concrete mixing main machine which comprises a hollow box body, a mixing mechanism is arranged in the box body, the mixing mechanism comprises a rotatable shifting plate, a filter screen is arranged on the lower side of the mixing mechanism, and the shifting plate can abut against the upper surface of the filter screen. When raw materials such as gravel are added into the box body, the stirring mechanism stirs the raw materials, and most of the finer raw materials are stirred, uniformly mixed and filtered through the filter screen, so that particles of a small part of the larger raw materials are filtered to the upper surface of the filter screen; and in the rotating process of the stirring plate, particles of large raw materials are repeatedly stirred, so that the particles of the large raw materials become fine and are filtered to the lower side of the filter screen to be discharged, and the effect of improving the fineness of concrete discharged by the stirring main machine i