The invention discloses a low-medium radioactive waste disposal repository with an airborne radioactive filtering and discharging function. An annular groove for filling fine sand is arranged in an inner lining; a ventilated concrete plate is arranged at the top of the inner lining; a crushed rock layer is arranged at the top of the ventilated concrete plate; and an inner ventilated concrete wall, an outer ventilated concrete wall and a filtering fine sand layer are arranged at a connecting part of a conveying and unloading channel and a top cover. The invention further discloses a low-medium radioactive waste disposal method with the airborne radioactive filtering and discharging function; the method comprises the following steps: building the inner lining; fully filling fine sand into a gap between the inner lining and a waste bag; pouring the ventilated concrete plate into the top of the inner lining and stacking at the top of the ventilated concrete plate to form the crushed rock layer; and building the inner ventilated concrete wall, the outer ventilated concrete wall and the filtering fine sand layer in the conveying and unloading channel. The low-medium radioactive waste disposal repository and method, provided by the invention, can prevent a condition that gas is accumulated and has excessive pressure to influence a cave structure, and can also be used for filtering radioactive substances in aerosol, without influences on water resistance of a cave, so that the low-medium radioactive waste disposal repository and method can be widely applied to the field of nuclear power.