In this report, the analogies of the maximum allowable liquid and gas velocities in various countercurrent gas-liquid contactors of column type are considered analytically. That is, by plotting the flooding points of various columns in a gas-liquid separated coordinates, the similar curves have been obtained in each column. Because the difference of these curves is due to the shape of each column, the difference of each shape must be corrected and evaluated as a ahape factor. Then, by containing this factor in coordinate variables, various flooding points in each column may be correlated by a single curve. If this correlation curve is used, the flooding velocity can be estimated easily, and the maximum allowable liquid and gas velocities in these countercurrent contactors of column type can be compared.