In this letter, a novel design of high tunable polarization rotator (PR) based on nematic liquid crystal (NLC) photonic crystal fiber is proposed and analyzed. The tunability of the proposed PR results from the change of the optical properties of the NLC with the temperature or external electric field. The simulation results are obtained using the full vectorial finite-difference method as well as the full vectorial finite-difference beam propagation method. The numerical results reveal that the suggested PR can provide a strong polarization conversion ratio of 99.81% with a device length of 1072 ??m.