Abstract: The sensor technology for high power microwave vector field by using recording characteristics of magneto-optic crystal is described in this paper. The multipoint array measurements on the microwave field of the cacinotron oscillator indicate that the sensor system has no effect on the measured field and has an anti-interference ability, its spatial resolution is 1mm. The sensor can measure the field’s main modes TM01,TE01 and TE11, and the field intensities and powers of these modes. The estimations of the total power agree well with the results which are measured by horn coupler.