The invention relates to a plumbum 
telluride (PbTe) or 
graphene nanocomposite material and a preparing method thereof. The plumbum 
telluride (PbTe) or 
graphene nanocomposite materiall is characterized by the following steps: using a compound of plumbum (Pb) and a compound of tellutide (Te) as raw materials, respectively dissolving the two compounds into deionized water according to the stoichimetric ratio of the plumbum 
telluride (PbTe), preparing a solution containing plumbum and a solution containing tellutide (Te) with same concentration from 0.01 mole per 
liter to 0.1mole per 
liter; dissolving 
graphite oxide into the deionized water, performing 
ultrasound for 0.5 hours to 2 hours, preparing a 
graphite oxide solution with a concentration from 0.5 milligram per mini 
liter to 2 milligrams per mini liter; adding the 
graphite oxide solution into the solution containing plumbum, performing 
ultrasound for 0.5 hours to 2 hours, adding the solution containing tellutide, adjusting potential of 
hydrogen (pH) to be 9 to 12 by adding strong alkali, adding 
reducing agent, sealing membrane, placing in 
warm water bath, reacting with stirring for 8 hours to 24 hours at the temperature between 60DEG C and 100DEG C, collecting products, washing by deioniaed water, 
drying, and obtaining the plumbum telluride (PbTe) or 
graphene nanocomposite material; and adding the 
graphite oxide at 1%-30% of the theoretical 
mass of the plumbum telluride (PbTe). The plumbum telluride (PbTe) or graphene nanocomposite material and thepreparing method thereof has the advantages of simple technology, low cost and the like and having small plumbum telluride (PbTe) particles with 20 nanometers to 60 nanometers and wide application prospect.