Abstract: A double cosine self-suction nozzle was designed based on the spraying inspiration. The influence of operat-ing parameters on the bubble size distribution in a double cosine self-suction nozzle was analyzed using methyl isobutyl carbinol (MIBC) as the frother. Bubble Sauter mean diameter of nozzle was investigated at different concentrations of frother,inflow pressure,sampling height,nozzle distance,and the suction capacity of the nozzle was researched under different inflow pressures using the image analysis technique. The results show that with the increase of frother concen-tration,the Sauter mean diameter (d32 ) decreases until the critical coalescence concentration (CCC) was determined as 0. 112 mmol / L above which the d32 is constant. With a higher inflow pressure,the constant is lower and the scope of bubble size distribution becomes narrow with the increases of the smaller bubble content. For example,the Sauter mean diameter was 0. 32 mm and the content of bubble middle size distribution was 40. 73% when the inflow pressure P is 0. 14 MPa. The d32 decreases with the increase of inflow pressure,nozzle distance and sampling height. The decrease ( increase) tread changes slower when the frother concentration reaches the CCC. With the inflow pressure the inspira-tory capacity increases linearly,and the inspiratory capacity is larger when the nozzle distance increases.