Recirculating aquaculture filtering device

The invention relates to a recirculating aquaculture filtering device. The recirculating aquaculture filtering device comprises filtering modules, which include a lower filtering module and an upper filtering module arranged in a nested mode in the lower filtering module; the upper filtering module comprises an upper inner drum, a sterilizing cavity arranged inside the upper inner drum, and a filter filtering cavity arranged between the upper inner drum and the sterilizing cavity; the lower filtering module comprises an outer drum, a second filtering cavity arranged inside the outer drum, and a third filtering cavity arranged between the second filtering cavity and the outer drum; the inside of the sterilizing cavity is provided with ultraviolet lamp tubes for sterilizing sewage; the inside of the first filtering cavity is provided with first filtering mediums for achieving first filtering on the sewage; the inside of the second filtering cavity is provided with second filtering mediums for achieving second f