Coalescence frequency and coalescence time were measured in electrolyte solutions. Marrucci model was acceptable to predict the coalescence time of one pair bubble in the dilute solution of electrolytes. Transition concentration decreased with increase of bubble forming frequency. This tendency was same as the results in low molecular alcohol solution. For a bubble column study, the effects of electrolyte on the gas holdup and bubble characteristics were investigated. The inhibition effect of bubble coalescence of the K2SO4 was slightly higher than that of the KCl at a same ionic strength. In this work, transition concentration was 0.36 kmol/㎥, which is larger than the value predicted in pair bubble study.