The invention discloses a chain belt type fire grate for a boiler. The surface of a metal fire grate body of the chain belt type fire grate is coated with protection paint. The protection paint is prepared by the following steps that firstly, by weight, 1-2 parts of methanol polyoxyethylene ether phosphate, 1.7 parts of sodium 4-(2-octanoyloxy ethoxy carbonyloxy) benezensulfonate, 3.6 parts of polyethylene glycol, 0.7 part of disodium hydrogen phosphate and 17 parts of modified water soluble phenol-formaldehyde resin are sequentially put into 20 parts of deionized water, uniform stirring is conducted; and secondly, by weight, 2-3 parts of polybutylene terephthalate, 1.2 parts of alkyl group sodium sulfate, 0.7 part of octadecylamine oleyl sarcosinate, 1.6 parts of alkylolamides polyoxy ethane ether and 2.3 parts of polyoxyethylene ether are sequentially put, stirring continues till mixing is uniform, and the protection paint is prepared. According to the chain belt type fire grate for the boiler, the surface of a metal fire grate body of the chain belt type fire grate is coated with the protection paint, and long-term usage of the fire grate can be guaranteed.