The utility model discloses a semi-automatic batching system for size mixing. The semi-automatic batching system comprises a mineral powder stock bin and a stirrer, and is characterized in that the mineral powder stock bin is connected with a batching barrel with a pressure sensor by a lifter, wherein a discharging hole in the bottom of the batching barrel is communicated with the stirrer by a discharging valve; an additive material box and a tap water pipe for adding water for the stirrer are further arranged on the upper part of the stirrer; a water metering solenoid valve is further arranged on the tap water pipe; the additive material box is communicated with the stirrer by the additive metering solenoid valve; the lifter, the stirrer, the pressure sensor, the water metering solenoid valve, the additive metering solenoid valve and the discharging valve are electrically connected with the PLC controller; a stock outlet is further arranged on the lower part of the stirrer, and the stock outlet is connected with a slurry extracting pump by a pipeline. The batching system disclosed by the utility model is free of manual weighing and batching, so that working efficiency and product quality are greatly improved, and a problem that environmental protection is not facilitated is overcome.