Abstract: The well type of Changning shale gas reservoir is cluster horizontal well. The water producing from the well is fracturing fluid residue, the type of it is CaCl₂, the salinity of it is between 29 g/L and 53 g/L. Aiming to the characteristic of water component and well type, the authors selected a foam agent which the foaming ability is greater than 160mm, 5 min foam steady ability is greater than 250 mm, foam-carrying capability is greater than 150 mL/15min, and developed a skid-mounted filling device for automatic foaming and de-foaming agent.The foaming agent and device have been successfully used in the wells of H3-1 and H3-2. The total increase of gas production is 0.49×10⁴ m³/d, which increased by 26.9%; the total increase of liquid production is 6.14 m³/d, which increased by 117%. It is confirmed that the foam-dewatering treatment has a good adaptability of Changing shale gas well.