Different degrees of high degree of substitution cationic starch (HCS) were prepared and applied in paper coating. Effects of HCS on coating properties and coated paper properties were investigated, and the comparison of effects of HCS and PDMDAAC was made. The results show that the best amount of HCS in coating formula is between 2% and 4%. When the amount of HCS is 4%, whiteness of coated paper was the highest. The color density was the highest when the amount of HCS is about 4% and the degree of substitution is 0.64. HCS with degree of substitution 0.849 is better than PDMDAAC in some respects, and the print image density achieved satisfactorily.