The utility model relates to a suspending agent blending reactor, which comprises a reactor. The suspending agent blending reactor is characterized in that a temporary storage tank is communicated to the lower side of the reactor via a collecting tube, the collecting tube is provided with a valve, a recycling tube communicated to the top of the reactor is arranged at the bottom of the temporary storage tank, and a water pump is connected to the recycling tube. The suspending agent blending reactor has the advantages that after the reactor is flushed by cleaning water, the cleaning water containing residual suspending agent enters the temporary storage tank via the collecting tube after the valve is turned on, the water pump can be opened when in next process for blending the suspending agent, and the cleaning water containing suspending agent is pumped into the reactor to be blended, thereby avoiding waste of resources.