Hydrolyzed polymaleic anhydride (HPMA) and polyethylene glycol monomethyl ether(MPEG) synthesized a kind of polycarboxylic grinding aid, the esterification was prompted by the mechanical force during the process of cement grinding. The effects on cement grinding and mortar property were tested from HPMA, MPEG, the mixture of HPMA and MPEG, and the resultant of HPMA and MPEG. The results showed that the mixture of HPMA and MPEG and the resultant of HPMA and MPEG had better grinding performance than HPMA and MPEG, and which can improve the fluidity and early strength of cement mortar. Laser Raman spectrum tests showed that the resultant of HPMA and MPEG had a similar Raman shift spectrum with the mixture of HPMA and MPEG, when they were adsorbed on the cement particle surface after co-grinding.