Abstract: Bubble volume is a key parameter determining the work performance of bubble filtration. When multi-orifice is employed as aeration appliance, the constructions of multi-orifice and air chamber below the plate have significant influence on bubble detachment volume. Visual experiments were conducted to study the influence of aeration appliance construction on the bubbling performance. The results suggest that multi-orifice possesses more perfect bubbling capacity at the condition that there is no water in air chamber. The effective bubbling time is applicable to characteristic the bubbling performance. Only under the condition that the gas flow rate is 0.35-0.7 L/min and the pitch of holes is below 6 mm, the influence of pitch of holes on bubbling performance can be considered. The orifice number in multi-orifice should be designed to guarantee that bubble detachment volume is mainly determined by air chamber volume.