The parameters of the plasma produced by ECRH in the magnetic mirror system are measured using double probe. The distribution of the velocity of the electrons produced by ECRH in the magnetic mirror machine is anisotropic. In this experiment, the average value of the ratio of the parallel and perpendicular energy of electrons is determined by measuring the turning point of the particles of plasma and using mirror ratio. In the magnetized plasmas, the cutoff, resonance and propagating of the microwave is studied by detecting microwave using antenna.