The invention discloses a semi-automatic tinning brush plating machine for a copper bar, and belongs to the technical field of copper bar production. The semi-automatic tinning brush plating machine for the copper bar comprises a machine body. A fixed clamping device is fixedly installed at the front end of the machine body, the U-shaped copper bar is fixed to the fixed clamping device, a Y-axis moving mechanism is connected to one side of a moving column, an X-axis moving mechanism is installed on the top of the moving column, an electrocleaning liquid coating mechanism, an intermediate watercleaning mechanism and an electroplating liquid coating mechanism which are distributed side by side are connected to the front side wall of the X-axis moving mechanism through a mounting seat, and the mechanisms of the electrocleaning liquid coating mechanism and the electroplating liquid coating mechanism are the same. Two groups of chemical pumps are further installed at the rear end of the machine body, and the chemical pumps are connected with the electrocleaning liquid coating mechanism and the electroplating liquid coating mechanism through conveying pipelines correspondingly. According to the semi-automatic brush plating machine for tin plating of the copper bar, previous manual operation ways can be replaced, full-range coating of the front, back, top, bottom, left and right faces of the copper bar is realized, the labor requirements are reduced, the brush plating time is further shortened, and the production efficiency is improved.