The overflow filter element can be used for exhaust ports on various drainage bags. The overflow filter element can allow air to be discharged freely through the waste liquid collection bag. Once in contact with the liquid, the filter element produces a self-sealing effect to effectively prevent liquid overflow and prevent liquid pollution to the instrument and the environment. The anti-overflow filter element is precise in size and can be assembled in the breathable cavity of the urine bag by pressing, and maintains the pressure balance during the filling process of the urine bag. It is very convenient to empty the liquid in the bag when discarding, so as to avoid the leakage of liquid at any stage.