Provided is a closestool free of scaling. A toilet cleaner solution or acetin in a plastic bottle can slowly flow out to be mixed with water in a water tank, and then mixed liquid is used for flushing the closestool, so that the automatic closestool flushing process is achieved. The closestool is ingenious in design of avoiding scaling, simple in structure, low in manufacturing cost and worthy of application and popularization, and time and labor are saved so that the public can conveniently use the closestool.