Controlled stacking of different two-dimensional (2D) atomic layers hold great promise for significantly optimizing the optical properties of 2D materials and broadening their applications. Here, vertical 2D MoS₂/Bi₂Te₃ heterostructures with high crystallinity and optical quality have been successfully constructed, through drop-casting 2D Bi₂Te₃ flakes on chemical vapor deposition (CVD)-grown MoS₂ flakes. Based on our homebuilt micro Z-scan and pump-probe measurement, we precisely investigated and compared the nonlinear optical (NLO) performance of an individual micro-sized MoS₂ flake before and after stacking 2D Bi₂Te₃ nanoplates. Moreover, layer-dependent ultrafast carrier dynamics of CVD-grown MoS₂ flakes were also explored. Owing to the efficient charge transfer from the monolayer (1 L) MoS₂ to 2D Bi₂Te₃, the 1L MoS₂/Bi₂Te₃ heterostructure demonstrated excellent NLO performance with superior nonlinear saturable absorption coefficient and ultrashort carrier lifetime. Our work greatly enriches our understanding of 2D heterostructure and paves the way for designing new type of tunable 2D photonics materials by combining the optical advantages of different 2D materials.