Coalescence frequency and coalescence times were measured in electrolyte solutions. Marrucci model w as acceptable to predict the coalescence time of one pair bubble in the dilute solution of electrolytes. Transition concentration decreased with increase ut bubble forming frequency. This tendency was same as the results in low molecular alcohol solution. For a bubble column study, the effects of electrlyte on the gas holdup and bubble character istics were incestigated. The inhibition effect of buble coalescence of the KSO was slightly higher than that of the hCI at a same ionic strenth. In this work, transition cuncentration was 0.36 kmol nv, which is larger than the value ptedicted in pair bubble study.