The invention discloses a hearth soot blower which is composed of a Roots blower, a volume regulating valve, a transmitting tube front hose, a transmitting duct, an ice bunker, a spiral conveyer, a scanning platform, an ice pellet machine, an air cooler, a cold air hose, a cold air inlet pipe, a cold air outlet pipe, a recirculating blower, a cold air return hose and the like, wherein the Roots blower pressurizes air into the transmitting duct; the prefabricated ice pellets are filled into the ice bunker; the ice pellets are continuously and quantitatively added into the transmitting duct through the spiral conveyer and a blanking port so as to form the air-particle two-phase mixture; the mixture accelerates at the jet port to form a high-speed jetted ice pellet particle group; and the high-speed jetted ice pellet particle group is transmitted into the hearth and impacts the opposite hearth soot deposit wall surface to realize the soot blowing operation after short-time flying. The invention uses high speed ice pellets to realize soot blowing, has the advantages of low mass of soot blowing medium and favorable soot blowing effect, can greatly relieve the problems of thermal shock, load, efficiency and the like, basically eliminates dead spaces of soot blowing, is convenient to install and operate, and is applicable to hearth soot blowing (deslagging) of a station boiler.