The invention discloses a water-logging fireflooding oil deposit oil-based combustible blocking agent. The water-logging fireflooding oil deposit oil-based combustible blocking agent comprises a carrying agent, a combustible blocking agent main component and a combustion improver; the oil-based carrying agent serves as the carrying agent; the combustible blocking agent main component is one or more of residual oil, asphalt, paraffin, rosin, starch and coke or charcoal powder; the combustion improver is one or two of calcium peroxide and manganese oxide. The water-logging fireflooding oil deposit oil-based combustible blocking agent mainly aims at solving the problem that after multiple rounds of steam huff and puff, blocks are water-logged, stratum deficit is serious, the oil saturation ofimmediate vicinity of wellbores is very low, the moisture is larger than 99%, and fireflooding injection wells are prepared. Through carrying of the combustible blocking agent main component and thecombustion improver in oil, combustible organic matter is provided while the immediate vicinity of wellbores is subjected to profile control and blocking, so that ignition is uniform and combustion issufficient.