Two cofrequency ultrasonic fields were coupled directly by ultrasonic stationary coupling system to clarify Fe2O3/kerosene sludge medium and achieve the separation of Fe2O3/kerosene. Experimental results show that when sound intensity is close to 80% of the cavitation threshold value, stable stationary field can be formed in the sludge medium after the superposition of primary wave and secondary wave in the ultrasonic field. The acoustic radiation force drives Fe2O3 phase to cluster toward the wave node, the Fe2O3 phase above wave amplitude position floats by overcoming the gravity, and the Fe2O3 phase below wave amplitude position subsides so that the suspension effect occurs in the kerosene phase and the clarification and separation of sludge is achieved. When sound intensity is less than 30% of the cavitation threshold value, the suspension effect of ultrasonic field on kerosene phase disappears. In this case, kerosene phase floats on the surface of sludge medium but the separation of Fe2O3/kerosene cannot be realized.