In this paper, a grapefruit microstructure fiber (GMF) temperature sensor coated with liquid crystal (LC) based on waist-enlarged taper is proposed and fabricated, and its temperature sensing characteristics are analyzed. The waist-enlarged taper is formed at the fusion point between single mode fiber (SMF) and GMF. The capillary glass tube is sleeved outside GMF, LC is filled into the capillary glass tube, and its two ends are finally sealed to form a sensor.The experimental results show that when the length of GMF is 2.5 cm, the temperature sensitivity of the sensor can reach up to 195.3 pm/°C in the range of 30—90 °C, and it has a good stability for reuse. Thereby, it can be used in biochemical, industrial production and other temperature detection areas.