Fabrication methods of SiO2 optical microsphere cavities and tapered fibers are introduced. Using a tunable single-mode NewFocus laser (short-term linewidth of 300 kHz) with an adjustable extent of 1520-1570 nm as the excitation optical source,whispering gallery modes (WGM) of microsphere with a diameter of 150 μm are achieved through coupling a tapered fiber with waist diameter of 1.2 μm. The microsphere and the tapered fiber are all fabricated by experimental laboratory setup. Based on the microsphere cavity′s temperature distribution,binding the thermal expansion coefficient and the thermo-optical refractive index effects,resonant spectrum shift(2.5 GHz/℃)induced by the high pump power in the microcavity is analyzed. The experiments indicate that controlling the WGM pump power is an effective way to suppress microcavity thermal effects,and in this way it is easy to fulfill a stable high quality factor (Q) model. Through adjusting the tapered fiber pumping angle,higher-modes are suppressed effectively,and an ultra-narrow linewidth about 22 MHz is measured. The corresponding Q of this microsphere is 107.