A highly sensitive temperature probe based on a liquid cladding elliptical micro/nanofiber is proposed, which exploits a fiber loop mirror with an output port probe for remote and highly-sensitive measurements based on evanescent field coupling. The thermo-optical effective liquid cladding avoids the influence of other environmental parameters (except for temperature), while protecting the micro/nanofibers from external disturbance and contamination. This renders the sensing probe only sensitive to temperature changes, making it suitable for real-world temperature measurements. An isopropanol cladding elliptical microfiber with a diameter of 3.4 µm demonstrated a sensitivity of -16.38 nm/°C for a remote temperature measurement.