The EDTA dianhydride reacted with diazacrown ethers to obtain the water-soluble EDTA-diazacrown ether polymers 1～3. The effects of crown ether ring in the polymer chains including its cavity size on the solubilization of barium sulfate to water were investigated by comparison with the crown ring-free analogue 4. The result shows that the polymer 2 is the efficient solubilizer of BaSO4 and the highest solubilization efficiency of the BaSO4 to water is up to 72.5%.