Abstract: The effects of ion types,temperature and scale size on the barium sulfate scale elimination were investigated by means of applying ionic liquids with different properties to descale barium sulfate scale.The results show that the ionic liquid CH₂CH₃)₃NHAl₂Cl₇ has a better dissolvability and a higher dissolving rate for the barium sulfate scale,which is enhanced greatly with the increase in the temperature and the decrease in the scale size (when the temperature increases from 60℃ to 70℃ and the size of the scale decreases from 600~1 000 μm to 100~200 μm,then the descaling rate increases from 5.00% to 31.6%).The types of cation and anion in the ionic liquid affect the scale elimination greatly.The dissolving effect of hydrophilic ionic liquid CH₂CH₃)₃NHAl₂Cl₇ with higher nonpolarity is much greater than that of the hydrophobic ionic liquid[BMIM]PF6 with higher polarity (under the same condition,the descaling rate of CH₂CH₃)₃NHAl₂Cl₇ is 22.45%,but the descaling rate of[BMIM]PF₆ is only 0.47%).Meanwhile the descaling effect of ionic liquid CH₂CH₃)₃NHAl₂Cl₇ for barium sulfate scale is more obvious than that for the calcium carbonate scale.