In order to improve the sensitivity of the temperature sensor, this sensor based on a microfiber interference and nanomaterial (boron nitride (BN) dispersion) encapsulation has been proposed in this study. The microfiber interference has a simple fabrication process, which was manufactured by using a butane flame brushing for tapering a commercial multimode fiber to micron scale. The smaller the diameter of the microfiber is, the stronger the evanescent field is.The interaction between the evanescent potential field and the external environment was enhanced. It was a trade-off between sensitivity and stability of microfiber interference, with the selected diameter of 12.3?m in the experiments. This microfiber interference was encapsulated in a capillary tube including BN dispersion with high thermo-optical coefficient to form this senor. In order to prevent liquid leakage, both ends of the capillary tube were sealed with the ultraviolet (UV) glues. The microfiber interference spectrum was stable after sealing with UV glue. The refractive index of the BN dispersion was more sensitive to temperature changes, which results in wavelength shift of microfiber interference. Therefore, the temperature response of this senor encapsulated with BN is measured by observing the drift of the transmission spectrum. The results show that the blueshifts of the wavelength occurs with the temperature increases, and the sensitivity of the temperature sensor encapsulated with BN can up to －0.2878?nm/°C, which is more than 10 times higher than without BN encapsulation (the sensitivity of －0.0297?nm/°C). The concentration of BN dispersion has little effect on the temperature sensitivity. The sensor has the advantages of small structure, light weight, low cost, and high mechanical properties. Moreover, the encapsulation can protect the microfiber interference from sensing deformation caused by environmental changes and contamination of thesensing part by external impurities, which can improve the accuracy of the experiment. This sensor has great application potential in the field of temperature sensing.