The invention discloses a self-adsorption filtering device for a heat source tower and belongs to the technical field of heat source towers. The self-adsorption filtering device comprises a main body part composed of structure supporting ribs and a self-adsorption filtering screen and an impurity collection tank arranged around the main body part. The structure supporting ribs form a framework of the main body part. The self-adsorption filtering screen is of a structure with an inclined face, arranged among the framework and integrally connected with the structure supporting ribs. The impurity collection tank is of a U-shaped structure and integrally connected with the bottom of the self-absorption filtering screen. The self-adsorption filtering device for the heat source tower is simple in structure, convenient to manufacture, capable of efficiently filtering impurities such as leaves and flocculation in circulating fluid in the heat source tower, free of interrupting the operation of the fluid of the heat source tower when the impurities are eliminated, capable of achieving continuous operation and extremely convenient to use.