The invention discloses a water tank type cleaning machine convenient to observe. The water tank type cleaning machine convenient to observe comprises a water tank body with a cleaning space and a covering plate arranged on the water tank body, and is characterized in that the covering plate comprises an upper cover and a lower cover which are made of glass, an interlayer is formed between the upper cover and the lower cover, a metal framework wraps the periphery of the upper cover and the lower cover, and a transparent observation window is formed in the center of the covering plate. Through the double-layer glass structure and a combined structure with the metal framework and the glass, the water tank type cleaning machine convenient to observe saves energy, protects the environment, reinforces the strength of the covering plate and makes it possible that a sealing strip can be arranged. The sealing strip is arranged in the position where the covering plate is matched with the water tank body, the water inside the water tank body is sealed inside and is prevented from splashing outwards and causing personal injuries or other accidents in the cleaning process, and due to the sink connecting method, even though the sealing strip ages and is insufficient in sealing, the leaked water can be limited at a step part and can not be splashed out.