The invention relates to a system for treating a tar residue through a totally enclosed anaerobic pyrolysis reaction. The system comprises a proportioning and feeding unit, an anaerobic pyrolysis reaction unit, a pyrolysis gas recovery unit and a fuel-gas tail gas recovery unit, wherein the proportioning and feeding unit consists of a super centrifuge, an oil residue collection intermediate tank and a tar residue conveying pump which are connected in sequence; the anaerobic pyrolysis reaction unit consists of a pyrolysis reaction kettle and an air preheater; the pyrolysis gas recovery unit consists of a cyclone residue remover, a secondary settling tank, a condenser and an oil-water separator which are connected in sequence; the fuel-gas tail gas recovery unit consists of an exhaust gas cleaning system and a draught fan through connection. The system has the characteristics of being simple in process flow, easy to operate, low in investment, good in environmental protection effect and low in energy consumption, and furthermore, is particularly applicable to a coking plant which has a high environmental protection requirement and has no ways for a tar waste residue.