The present invention discloses slow-release cationic anti-mud polycarboxylic-type high performance water reducer and a preparation method thereof. The slow-release cationic anti-mud polycarboxylic-type high performance water reducer is successfully synthesized from an unsaturated carboxylic acid, a polyether macromonomer, a cationic unsaturated monomer, an unsaturated esters, a crosslinking agent, a chain transfer agent, an oxidizing agent and a reducing agent as raw materials at room temperature without heat source. By introduction of the long-chain-ester crosslinking agent and the cationic unsaturated monomer, the slow-release cationic anti-mud polycarboxylic-type high performance water reducer has good slow-release and anti-mud effects, is low in admixing volume, high in water-reducing rate, excellent in slump retention ability, and not sensitive to mud contained in sand and stones, and the process does not require an additional heat source, an be carried out at room temperature, and is low in investment, low in cost, and suitable for large scale promotion and application.