The invention provides an oil refining sewage biological treatment device which comprises a hydrolysis acidification unit, an aeration unit, a primary sedimentation unit, a LINPOR unit and a final sedimentation unit, wherein the hydrolysis acidification unit, the aeration unit, the primary sedimentation unit, the LINPOR unit and the final sedimentation unit are sequentially connected, a sludge bed is arranged in the hydrolysis acidification unit, sewage enters from the bottom of the hydrolysis acidification unit, ascends and passes through the sludge bed, the sludge bed is used for intercepting and adsorbing granular substances and colloidal substances in the sewage; pure oxygen is introduced into the aeration unit.