The invention relates to the technical field of environmental protection facilities, and provides a filtering system and method. The filtering system comprises a waste liquid clear liquid storage, a filter, a filtering screen storing box, a filtering screen recovering box and a press filter used for extruding and driving a first filtering screen; one end of the first filtering screen is rotatablymounted on the filtering screen storing box, the other end of the first filtering screen is rotatably mounted on the filtering screen recovering box, and the first filtering screen penetrates throughthe filter; the press filter is located in the filter, and the first filtering screen is mounted on the press filter; the waste liquid clear liquid storage communicates with the filter; and the filteris provided with a waste liquid inlet, and the first filtering screen is located under the waste liquid inlet. The filtering system can pretreat a penetrating fluid, thus the problems that disposingof an existing penetrating fluid or other waste liquid is low in automatic degree and high in disposing cost, and a spraying gun is prone to being blocked are solved, the types of the penetrating fluid or other waste liquid are not limited, adaptability is high, and the filtering system and method are suitable for industrial production occasions.