Abstract: The ion temperature in Tokamak plamsa is an important parameter. A vibration mirror instrument for measurement of plasma ion temperature was established, and this system consists of a 0.5m Czerny-Turner spectrometer and a vibration quartz mirror in front of the exit slit of the spectrometer. The CV (227.1nm) line shape was measured by vibrating the mirror, which was controlled by a scan controller, the time dispersion of the system is less than 10ms and the error is less than 20eV.The ion temperature in HT-6M Tokamak was derived from the Doppler broaden of CV line during OMH and ICRH. The result shows that the ion temperature rises from 200eV to 300eV during ICRH. The equipment can be widely applied to small and medium sized Tokamak.