Cationic polymers, a kind of polyelectrolyte, are widely used in petroleum exploitation, papermaking, textile, wastewater and sludge treatment, etc. because of the properties of good water-solubility, regluting iondegree and molecular weight, effective and nontoxic. Methacryloyloxyethyltrimethyl ammonium chloride polymer is one of the representatives. The research progress in the polymerization and application of poly-methacryloyloxyethyltrimethyl ammonium chloride PDMC and poly-methacryloyloxyethyltrimethyl ammonium chloride-co-acrylamide P(DMC-AM) are reviewed in this paper. Firstly, PDMC synthesis progress is summarized and the latest research direction is picked up. Then, the research progresses on aqueous polymerization, inverse emulsion polymerization and dispersion polymerization are summarized and discussed, according to the classification of polymerization. Furthermore, the differences of P(DMC-AM) in practical sludge dewatering applications are compared. Finally, the existed difficulties on the synthesis and application are concluded and its future development tendency are predicted.