The invention relates to a T/P92 heat-resistant steel welding rod and a preparation method thereof. According to the T/P92 heat-resistant steel welding rod, the chemical element composition of a corewire is controlled to be within a standard scope of the chemical composition of deposited metal by adopting a core wire transition method, and the relatively-high-alkalinity low-hydrogen design is adopted for a coating. Compared with the prior art, the T/P92 heat-resistant steel welding rod provided by the invention has the advantages that in the welding process, a stable electric arc is ensured,the splashing phenomenon is basically avoided, the slag detachability is high, a clear molten pool is ensured, the forming of a weld is aesthetic, and the welding rod operating property is good; and the deposited metal strength, the impact toughness and the like are very high.