Novel cationic spherical polyelectrolyte brushes (CSPBs) were prepared by photoemulsion polymerization. Dimethyl diallyl ammonium chloride was grafted onto the surface of polystyrene particles bearing a thin layer of photoinitiator that was prepared by Schotten-Baumann reaction of Darocur 1173 and Methacryloyl chloride. Transmission electron microscopy (TEM) was used to analyze the size and shape of CSPBs, the average diameter of these particles with uniform spherical structure was ca.170nm. A link to the use of this system as a model for retention and drainage aid in the papermaking process was described. Dynamic drainage experiment indicated that the shortest drainage time was 23.2s when the percentage of the aid was 0.04%(wt). The retention effect of the aid was tested that the highest of the first-pass retention was 70.89% when the percentage of aid was 0.035%(wt).