The invention discloses an anti-scaling system and method for a wet deslagging system of a thermal power plant. The anti-scaling system comprises a controller, a fine treatment regeneration system, afirst online pH meter, a fine treatment regeneration acidic wastewater delivery valve, a fine treatment regeneration alkaline wastewater delivery valve, a chemical regeneration system, a second onlinepH meter, a chemical regeneration acidic wastewater delivery valve, a chemical regeneration alkaline wastewater delivery valve, a desulfurization system, a slag removal system water replenishing tank, a slag removal system water replenishing tank delivery pump, a slag conveyor, a boiler, a slag overflow tank, a concentration tank, a clean water tank and a third online pH meter, According to the system and the method, the scaling problem of pipelines and equipment of the wet deslagging system can be prevented and the disposal problem of regenerated wastewater of the whole plant can be solved and the cost is low.