The online monitoring of the insulation status of transformers is important to guarantee the stability and safety of a power system. Dissolved gas analysis (DGA), which employs highly sensitive gas sensors for detecting dissolved gas in transformer oil to reflect the insulation performance of such equipment, is a promising method to realize this purpose. In this paper, we used density functional theory to analyze the potential of a new 2D material, the Pt-doped WTe 2 (Pt-WTe 2 ) monolayer, to detect typical fault gases (including H 2 , CH 4 , and C 2 H 2 ) in transformer oil. Results indicated that the most stable structure of Pt-WTe 2 monolayer could be obtained by doping Pt atom right above the W atom, and its suitable adsorption performance allows Pt-WTe 2 to be used as a sensor and a scavenger for C 2 H 2 and H 2 , respectively. This article illustrates the mechanism of the interaction of Pt-WTe 2 with H 2 , C 2 H 2 , and CH 4 , which lays the foundation for the preparation of gas sensors for DGA.