In this paper, we experimentally investigate the tuning characteristics of laser modes for an ultrahigh-Q Er³⁺-doped microbottle resonator (MBR) based on the whispering gallery mode (WGM). Thanks to the optimized Er³⁺ doping technique, the laser threshold could be as low as 70 µW. Benefiting from the abundant axial modes and radial modes of the MBR, our experiments demonstrate that the number of laser modes can be flexibly controlled by varying the pump power, adjusting the coupling positions along the axis of the MBR, as well as modifying the coupling diameter of the tapered fiber. The laser mode switching is performed from single-mode to multimodes. Furthermore, different from the traditional external tuning method, we propose a simple and stable approach for continuous wavelength tuning of the laser mode based on the thermal effect associated with the high Q MBR. By precisely adjusting the pump laser wavelength, the emitted laser wavelength can be tuned over a range of 0.102 nm with a high linearity of 99.96%. The engineering of laser mode switching and precise wavelength tuning of the Er³⁺-doped MBR is expected to have promising applications in miniature tunable single-mode lasers, laser precision measurement, and so on.