The invention discloses a blending tank liquid surface air bubble eliminating device. A liquid level meter and a stirrer are arranged in a blending tank, the blending tank is externally connected with an air suction tube and a secondary slurry mixing manifold, the output port of the air suction tube is communicated with an air suction port of a centrifugal fan, and the power input end of the centrifugal fan is in driven connection with a motor. The exhaust port of the centrifugal fan is connected with one port of a liquid discharging tube, the other port of the liquid discharging tube is communicated with the secondary slurry mixing manifold, and the secondary slurry mixing manifold is connected back to the blending tank. The blending tank liquid surface air bubble eliminating device sucks air bubbles produced during liquid blending in the blending tank through work of the centrifugal fan, eliminates the air bubbles through the rotary centrifugal force of an impeller and converts the air bubbles into liquid to be discharged out, facilitates improvement of measurement accuracy of the liquid level meter of the blending tank, effectively reduces the labor intensity and improves the operating quality and operating efficiency.