Traditional sulfonated melamine resin (SMF) as high-range water-reducer easily causes a big slump loss and high bleeding ratio of concrete, sodium lignosulfonate grafting melamine resin (SLMF) was synthesized with (NH4)2S2O8 as the radical initiator, and the optimal process variables were obtained. Both of the results of IR and the properties of SLMF showed that sodium lignosulfonate was successfully grafted into SMF. SLMF synthesized under the optimal process variables had good properties of dispersion effect and water retention. When the mass ratio of water to cement was 0.29, the fluidity of cement paste with the addition of 0.6% (mass fraction) of SLMF was 253mm. The fluidity loss within 90 min and the water bleeding ratio within 140min decreased to 61.8% and 1.61% from 100% and 4.84%, respectively. The results indicate that SLMF overcomes the shortages of SMF, and hence exhibits potential application in high-range water-reducer.