Alloying in two-dimension has been a hot spot in the development of new, versatile systems of optics and electronics. Alloys have been demonstrated to be a fascinating strategy to modulate the chemical and electronic properties of two-dimensional nanosheets. We firstly reported ultra-broadband enhanced nonlinear saturable absorption of Mo_0.53W_0.47Te₂ alloy at 0.6, 1.0, and 2.0 μm. The nonlinear saturable absorption of Mo_0.53W_0.47Te₂ saturable absorber (SA) was measured by the open aperture Z-scan technique. Compared to MoTe₂ and WTe₂ SAs, the Mo_0.53W_0.47Te₂ SA showed five times deeper modulation depth, 8.6% lower saturable intensity, and one order larger figure of merit. Thus, our research provides a method of alloys to find novel materials with more outstanding properties for optics and optoelectronic applications.