Whispering-gallery-mode microlaser is an important candidate for various applications such as optical sensing, spectroscopy, and communications. The ability to manipulate lasing modes and even to realize single-mode lasing emission is highly desirable. Here, we realize flexible manipulation of lasing modes in an erbium-doped silica microbottle cavity via an add−drop configuration, which possesses highly nondegenerate modes along its axial direction. An ultralow lasing threshold down to 89 μW is achieved in the erbium-doped microbottle cavity with ultrahigh quality factors up to 10 8 via a novel doping method. We realize selective suppression and extraction of the lasing modes by coupling a probe microfiber at different axial positions of the microbottle cavity. Importantly, a single-mode microlaser with a high side-mode suppression ratio up to 24 dB is achieved without mode hopping. Our scheme demonstrated here may have various promising applications ranging from single-mode lasing emission and switchable microlaser to optical communication.