Valley topology has emerged as a key concept for realizing new classes of quantum states. Here, we investigate Floquet-engineered topological phase transitions in anisotropic $1T^{\prime }\text{−}{\mathrm{WSe}}_2$ and its Janus derivative WSeTe monolayers, which exhibit valley-degenerate and valley-polarized characteristics, respectively. In $1T^{\prime }\text{−}{\mathrm{WSe}}_2$, a single topological phase transition (TPT) occurs from the quantum spin Hall state to the quantum anomalous Hall (QAH) state, involving one spin channel at both valleys simultaneously. In contrast, Janus WSeTe undergoes a two-stage Floquet-driven TPT that occurs within a single valley and sequentially involves two spin components. The intermediate phase manifests as a valley-polarized QAH state with a finite valley Chern number, while the final phase evolves into a high Chern number QAH state with distinct valley gaps. Furthermore, an in-plane anisotropic response of the TPTs is predicted under oblique light incidence, reflecting the intrinsic low-symmetry nature of the lattice. These findings provide a comprehensive understanding of Floquet-engineered valley-based topological properties and offer guidance for designing light-controllable valleytronic and topological devices.

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• Photoinduced effect
• Quantum anomalous Hall effect
• Topological phase transition
• Valley degrees of freedom
• Transition metal dichalcogenides