The utility model belongs to water purifier accessories processing field, concretely relates to automatic inflation device of water purifier pressure pot, aerating device comprises with an air chambera portion of aerifing, and the portion's of aerifing setting is above in the air chamber and communicate in the air chamber, the portion of inflating comprises an admission line and air plug, form aholding chamber between admission line and the air plug, the holding intracavity is provided with a ball valve, is provided with at least one gas pocket on the air plug, and air plug center departmentstill is provided with a through -hole. Through component reasonable collocation such as pressure bladder, pneumatic valve, ball valves, make the pressure pot aerify and become simpler, it is more convenient to operate, and the device design benefit, sealing performance is good, thereby the device having gas leakage to take place owing to there is the effect of pneumatic valve not worry when aerifing the completion simultaneously, influences machine performance, consequently, very big market prospect and economic value have.