<p>The thermal conductivity of two-dimensional transition metal dichalcogenides (TMDs) materials is significantly reduced compared to bulk materials due to the quantum size effect, which renders them highly application promising as thermoelectric materials. Here, we employ first-principles methods combined with the non-equilibrium Green’s functional formalisms (NEGF-DFT) to reveal the impact of pressure on the thermoelectric performance of monolayer, bilayer and heterostructure TMDs (2H-MoS₂, 2H-WS₂ and MoS₂@WS₂) materials. The thermoelectric performance of monolayer and heterostructure is significantly enhanced under specific low pressure, and the figure of merit (ZT) of monolayer MoS₂ and WS₂ can reaching up to 2.79 and 2.68 at 700&#xa0;K. Conversely, for bilayer materials, pressure led to a decrease in ZT. The simultaneous discovery of a unique phenomenon in Mo-based TMDs materials is that they can undergo transformation from N-type to P-type thermoelectric materials with high electrical conductivity under higher pressure. This is because the pressure causes different effects on the carrier motion at different high symmetry points. Additionally, another bilayer stacking mode is constructed, which successfully surpasses the thermoelectric performance of traditional bilayer MoS₂ by a specific pressure. This study shows a method to enhance the thermoelectric performance, and more importantly provides a theory that can predict the effect of pressure on the thermoelectric performance of all structures constructed from TMDs materials.</p> Graphical abstract <p></p>