Abstract: Based on self made sodium lignosulfonate,potassium persulfate( K2S2O8) as initiator with methacrylic acid could polymerize and prepare methacrylic acid graft and sodium lignosulfonate copolymer. The Infrared Spectrum and thermogravimetric analysis were applied to the structure characterization on the lignosulfonate and | ignosulfonate MAA graft copolymer and to investigate the synthesis conditions affected to the dispersion effect of the coal water mixture. The results showed that the best p lan of graft was a temperature of 75 °C,m( MAA) : m(LA) : m( H2O)= 1 : 3 : 150,and the quality fraction of K2S208 was 4%( relative to LA). The dispersant was appli ed to the Shenhua coal slurry test and the dispersant was verified with good dispersion role.