Abstract: A novel polycarboxylate additive was prepared by the graft copolymerization of propenyl polyoxyethylene ether. The preparation method was optimized by orthogonal and single factor experiments, the product was characterized and its application properties were investigated. Results showed that the optimal synthesis method was based on the reaction among 6. 0 g acrylic acid, 1. 6 g acrylamide, 1. 8 g initiator, 1. 0 g chain transfer agent and 35. 0 g propenyl polyoxyethylene ether at 80℃ for 2 h. The measured solid content of the product was 35. 4%. The modified monomers were successfully grafted to the main chain of the macromolecule, and the double bond was no longer existed in the molecule. Additive mass fraction of 0. 4% could assign proper Zeta potential, good dispersion and stability to the coal water slurry.