Abstract: The pressure difference method was applied to measure the air content ratio of the vortex-static minute bubble floatation column.The single factor and th e orthogonal test was applied individually to study the circulated pressure, the air intake quantity and the frother density factors affected to the air content ratio.Based 0 n the circumstance, the multi elements regression analysis method was applied to establish the regression model between the air content ratio and the three factors un der the test conditions.The results showed that the air content ratio would be increased with the air intake quantity and frother density increased.When the air intake qu antity was not fixed, the air content ratio would be increased with the circulated pressure increased.When the air intake quantity was fixed, the air content ratio would b e reduced with the circulated pressure increased.The effect of the three factors to the air content ratio would be from large to small in sequence individually as the circu lated pressure, air intake quantity and frother density.The error between the model calculation and the site measured value would be small and these values reached at a high accuracy. .