The invention discloses a tail heat recovery type dirt retention preventive oil burning boiler. A boiler chamber is mounted at the top of an oil burning boiler main body; a protective box is mounted at the bottom of the frontage of the boiler chamber; a water inlet is formed in the top end of the right side of the boiler chamber; one end of the water inlet is fixedly connected with a water feedingpipe; a water pump is mounted at the bottom end of the water feeding pipe; a furnace pipe is arranged in the middle of the interior of the boiler chamber; an exhaust pipe is mounted at the top end ofthe right side of the furnace pipe; the top end of the exhaust pipe is fixedly connected with a tail gas outlet; one end of the tail gas outlet is fixedly connected with a first-class tail gas pipe;a water storage tank is mounted at the bottom end of the first-class tail gas pipe; a helical pipe is mounted in the middle of the water storage box; the bottom end of the helical pipe is fixedly connected with a second-class tail gas pipe; and a filter is mounted at the bottom end of the second-class tail gas pipe. A plurality of convex cavities are formed in the outer side of the furnace pipe toincrease the contact area of the furnace pipe and the water body in the boiler chamber, so that the heat exchanging speed is accelerated, the steam output is increased, and high simpleness and practicality are realized to further improve the working efficiency of the oil burning boiler main body.