Abstract: The present invention provides an oil slurry filter, a filter unit including the oil slurry filter, a multiple-filter system including the oil slurry filter, and a multiple-stage filter system including the oil slurry filter. Due to the use of the filter component of flexible texture in the oil slurry filter of the present invention, the problems that the filter material is easily blocked by high-viscosity colloidal impurities, the regeneration efficiency of the filter is poor and the filtration efficiency is low are solved, and it is possible to make the backwash treatment of the filter residue more convenient and improve the regeneration efficiency of the filter. The present invention also provides a filtering process using the oil slurry filter to ensure long-term stable operation of the oil slurry filtering process.