The development of high-quality, stable, and cost-effective micro/nano dual-band lasing for multifunctional applications remains a crucial endeavor. In this study, we demonstrate high-Q dual-band whispering gallery mode lasing, emitting ultraviolet and blue lasing, using an independent core-shell microdisk. The GaN-based microdisk with InGaN/GaN quantum wells serves as the core, while a SiO 2 layer is deposited on the sidewalls to construct the core-shell structure. This independent structure is fabricated using the graphically epitaxial lift-off method, which effectively mitigates light leakage issues associated with the substrate and facilitates flexible device integration. Compared to the microdisk without a SiO 2 shell coating, the threshold of ultraviolet lasing in the core-shell microdisk is reduced by 1.6 times, the Q-factor is enhanced by 21.7%, and blue lasing is successfully achieved. To further enhance the lasing quality in the blue band, we employed temperature regulation, resulting in a 1.9-fold increase in Q-factor. Additionally, due to thermal expansion and thermo-optical effects, a blue shift in the lasing mode is observed with decreasing temperature, exhibiting a slope of 0.007 nm/K. The underlying physical mechanisms are thoroughly analyzed using steady-state and time-resolved PL, along with FDTD field simulations. In summary, the generation and control of dual-band lasing within a single microcavity present significant implications for the realization of multifunctional devices.