The invention relates to the water treatment industry, in particular to drinking water filtration, and discloses a water purifier with a turnover cover display window device. The water purifier comprises filtering inner containers and a lower filtering inner container bin. The filtering inner containers are fixed into the lower filtering inner container bin through filtering inner container fastening devices. Water ports in the lower ends of all the filtering inner containers are connected front and back to form a filtering channel. The water purifier further comprises a turnover cover provided with the display window device, vertical lugs arranged on the lower filtering inner container bin and the turnover cover respectively, and a shaft. The shaft, the vertical lug of the lower filtering inner container bin and the vertical lug of the turnover cover form a hinge swing mechanism connected with the lower filtering inner container bin and the turnover cover in a matched mode. The display window device is either a single-display-window device arranged on one side of the turnover cover or a double-display-window device provided with a running state display window device and a detection maintenance state display window device.