The invention discloses a composite PbSe-based thermoelectric material doped with Sr and Na and a preparation method thereof. The preparation method comprises the steps of firstly weighing Pb, Sr, Na and Se according to a stoichiometric ratio of Pb<0.98-x>Sr<x>Na<0.02>Se, mixing Pb, Sr, Na and Se, carrying out vacuum tube sealing smelting, and completing a phase formation stage of the phase. A sample after heat treatment is ground and put into a graphite die, and powder is manufactured into a block sample by adopting a rapid hot-pressing sintering technology, thereby being capable of acquiring a Pb<0.98-x>Sr<x>Na<0.02>Se thermoelectric material. Compared with traditional hot-pressing sintering, the preparation method disclosed by the invention has the advantages of uniform heating, high temperature rising speed, short sintering time and the like, and the sintered sample is obvious in performance variation. The thermal conductivity of the material is greatly reduced after being doped with Sr and Na, the Seebeck coefficient is increased, and a thermoelectric material with a high ZT value is acquired.