A novel temperature sensor has been proposed based on microfibre knot resonator packaged by polydimethylsiloxane (PDMS). Owing to the high thermal expansion and thermo-optic coefficients of PDMS, the resonant wavelength shifted obviously along with the changing of temperature. The experimental results indicated the approximate linear temperature sensing performance in the range of 24–38°C and 40–54°C, with the high sensitivities of 1.408nm/°C and 0.973nm/°C, respectively. Due to its excellent performances and easy fabrication process, the temperature sensor will be the promising candidate for monitoring the stability of air condition and organism.