Construction method and device for controlling flatness of column wall root concrete surface

The invention discloses a construction method and device for controlling flatness of a concrete surface at the root of a column wall, and the method comprises the following steps: (1) according to the condition of the root of a wall column, installing a flatness adjusting device in an overhanging manner, and connecting the flatness adjusting device with at least one vertical steel bar of the column wall; or the flatness adjusting device is installed in a vertical supporting mode; or the flatness adjusting device is installed in a vertical rib binding mode, and the flatness adjusting device is connected with the formwork or connected with the vertical main rib of the wall column in a binding mode; (2) when concrete is poured at the root of the column wall, a control part of the flatness adjusting device is selected to be arranged on the upper surface of the concrete according to different installation modes; or the control part is pre-buried in the concrete, the upper surface of the control part is flush with