Due to the composition-dependent properties of two-dimensional (2D) transition metal dichalcogenides (TMDs), alloying of existing dissimilar TMDs architecture is a novel and controllable route to tailor crystal structures with superior optical and optoelectronic properties. Here, we reported the hexagonal-phase WSe_1.4Te_0.6 alloy can enable great promise for enhanced saturable absorption response exceeding the parent component WSe₂ and WTe₂, with larger modulation depth and lower saturable intensity. These advantages allowed the 1064 nm passively Q-switched lasers based on WSe_1.4Te_0.6 to be more efficient, with pulse duration narrowed to 45%, and slope efficiency increased by 232%. Our findings highlighted the appropriate alloying of TMDs as an effective strategy for development of saturable absorbers.