Dispersant for paint

The invention discloses a dispersant for a paint. The dispersant is prepared from the following components: acrylic acid, methyl methacrylate, glycol, an organic solvent, modified diatomite, an initiator, sodium hydrosulphite and a neutralizer. The dispersant provided by the invention can reduce surface tension of the waterborne paint, improves wetting effect on pigment particles, allows the pigment particles to be stably dispersed in a liquid phase, can rapidly and firmly bond with surface groups of the paint and enables the pigment particles to stably suspend in a hydrosolvent so as to allow pigment to be well dispersed, thereby achieving optimal dispersion effect; and through addition of modified diatomite, the stability of the dispersant is greatly improved. During preparation of the dispersant, the initiator is added in multiple steps instead of one step in the prior art, so the molecular weight of resultant and product distribution are changed, and the prepared dispersant has good dispersion performance and good capability of tolerating changes of environment temperature.