To achieve highly sensitive temperature sensing, this paper proposes a micro/nano fiber temperature-sensing structure based on chip packaging. The optical field energy distribution of micro/nano fibers with different diameters and their Brillouin scattering spectra are analyzed. Based on the characteristics of various acoustic modes, the temperature sensitivity of micro/nano fibers under different acoustic wave modes are obtained using finite element simulation. The packaging structure and materials are designed and analyzed, with a chip-scale structure and PMMA chosen for packaging. The simulation shows that the maximum temperature sensitivity of the packaged micro/nano fibers is 4.83 MHz/℃, which is approximately 363% higher than that of the unwrapped fibers, demonstrating that chip packaging can effectively enhance the temperature sensitivity of micro/nano fibers.