Belonging to the field of dispersants, the invention provides a method for preparation of high mud resistant polycarboxylic acid dispersant by unsaturated halogenated 
hydrocarbon copolymerization and 
grafting with a cationic 
side chain. The method consists of: employing an unsaturated 
carboxylic acid monomer, an unsaturated halogenated 
hydrocarbon monomer, an unsaturated cationic 
quaternary ammonium salt 
monomer, a 
polyethylene glycol compound and the like as the raw materials, firstly conducting main chain copolymerization, then polymerizing the cationic 
side chain, performing functionalization, and finally carrying out etherification 
grafting so as to synthesize the excellent performance high mud resistant polycarboxylic acid dispersant material with unsaturated halogenated 
hydrocarbon copolymerized and grafted with cationic 
side chain, i.e. taking unsaturated 
carboxylic acid and unsaturated halogenated hydrocarbon as the reactants, conducting free 
radical polymerization to obtain a 
carboxylic acid-halogenated hydrocarbon 
copolymer main chain, using high valence 
cerium salt-
alcohol to initiate 
polymerization of an unsaturated cationic 
quaternary ammonium salt monomer so as to obtain a hydroxyl terminated cationic side chain, then modifying the hydroxyl terminated cationic side chain and the 
polyethylene glycol compound to obtain a functionalized side chain, and carrying out etherification 
grafting of the functionalized side chain on the carboxylic acid-halogenated hydrocarbon 
copolymer main chain. The method provided by the invention realizes high water reduction, 
slump loss resistance, high clay resistance and other multiple effects.