The invention discloses a liquid-foam separation method suitable for a wet-process phosphoric acid low-position flash evaporation cooling system. According to the method, the liquid discharging pipe of a liquid-foam separator and a material slurry pump suction pipe are separated, such that the liquid-foam separator is an independent separation device; the material slurry pump suction pipe is connected to a flash evaporation chamber in a vacuum manner, and the distance between the connection point and the liquid level of the flash evaporation chamber is 0.5 m; the ultimate vacuum degree of a control system achieves -65 kPa; the material slurry carried by the suction pipe is subjected to gas-liquid separation in the flash evaporation chamber; the separation height of the liquid-foam separator is more than or equal to 5 m; and the liquid discharging pipe of the liquid-foam separator is subjected to liquid sealing with process water, and the separated liquid-phase material is discharged into a ground groove so as to be recovered. According to the present invention, the method has advantages of stable and reliable operation, low investment, low cost and the like; with the method, the pipeline fouling problem is effectively eliminated, the smooth flowing of the liquid discharging pipe is ensured, the long-term normal liquid discharging is achieved, the material slurry is not sucked into cooling circulation water, phosphorus loss does not exist, the stability and the reliability of the process are improved, and the good promotion application prospect is provided for the improvement of the similar low-position flash evaporation cooling system.