The constant temperature filtering cutting fluid magnetic separation paper tape filter has good filtering effect: it can fully filter out various metal and non-metal impurities in the coolant (oil). When the dirty liquid falls onto the paper tape, fine chips and impurities are adsorbed onto the paper tape, and they also become the filtering layer to participate in the filtration, increasing the filtering effect of the paper tape. The paper tape filter device consists of a liquid tank, a collection tank, a filter non-woven fabric/paper tape, a magnetic roller separation device, a reducer, a transmission mechanism, a signaling mechanism, a liquid pump, and other components. The contaminated liquid containing a large amount of impurities during work is first separated by a magnetic roller separation device (optional when there are many magnetic impurities in the filtered liquid).