Millimeter wave radar is an ideal instrument for detecting the nonprecipitation clouds and weak precipitation clouds, but it is likely to cause velocity aliasing due to its short wavelength. Velocity dealiasing is an effective means of detecting wind field information with Doppler radar. Two methods aiming at velocity aliasing with the millimeter wave radar Range Height Indicator are put forward: humanmachine interaction method and automatic method, and tests are conducted with the measured data. It is proved that both methods are satisfactory in dealing with velocity aliasing. The comparison of the results also shows that the automatic method is more efficient than the humanmachine interaction method, but for the smaller isolated area, the latter has more advantages.