The invention relates to the fields of hot-dip galvanizing alloy technology and auxiliary equipment used therefor, and specifically relates to a dry and wet gas mixing and humidifying device for inhibiting zinc ash in hot galvanizing and a use method thereof. The device comprises a furnace nose (10), and is characterized by also comprising a water tank (1), a water inlet pipe (21), a water discharge pipe (22), an air inlet pipe (23), a flow meter (33), a water level gauge (41), a heater (42), a dew-point instrument (43), a dry gas header pipe (5), a dry wet gas mixing pipe (6), and a control device (7). The use method comprises the following steps in sequence: (i) introducing dry gas; (ii) humidifying the dry gas; (iii) mixing dry gas and wet gas; and (iv) regulating the dew point. The device and method have the advantages that the zinc ash is well inhibited, the strip steel quality is high, the control is accurate, and the automation degree is high.