The present invention discloses a filtering device with non-return function. The device comprises a body, a filter core and a valve core. The body is provided with a filter chamber, a water inlet, a water outlet and a single flow valve chamber; the water inlet communicates with the filter chamber; the filter chamber communicates with the single valve by a filtering water discharge hole; the water outlet is in communication with the single flow valve chamber. The filter core is arranged in the filter chamber, and connected to the filtering water discharge hole; and the volume of the filter core is less than that of the filter chamber. The valve core is arranged in the single flow valve chamber, and includes a valve ball, a valve seats and a spring; the valve ball sits on the valve seat; and the spring applies thrust on the valve seat, so that the valve ball is in sealing contact with the filtering water discharge hole. The invention has filtering and non-return dual functions.