The invention discloses a method for synthesizing chloroacetaldehyde through catalysis of aqueous solution of aldehyde. In the method, the aqueous solution of aldehyde is taken as a raw material, and the aldehyde is subjected to chlorination by controlling reaction temperature in the presence of a single or mixed catalyst; and after the reaction is finished, the product is subjected to distillation or suction filtration, and high-purity chloroacetaldehyde is obtained. The method has the advantages of high yield and light environmental pollution, and can be applied to preparation of a small amount of chloroacetaldehyde in a laboratory and industrial production.