Microwave discharge is a kind of non-polar mode, which may form plasma that has the characteristics of transient, low temperature, non-equilibrium and so on at atmospheric pressure. A microwave plasma experimental facility with quasi optical focusing reflector is introduced, including the atmospheric environment simulation chamber and microwave transmission focusing system. A non-uniform strong electric field of kV/cm magnitude formed by focusing microwave power in the chamber, with plasma motivated in the central region. The distribution of the electric field in the chamber is calculated and measured. The results are in good agreement. And the shape of the plasma is also consistent with the intensity of the electric field. The plasma images under different parameters were observed by the camera through the device. The capability of the device was verified, which laid a foundation for further study of microwave atmospheric breakdown.