Abstract: The paper proposes and studies an experimental scheme that tests microwave gas breakdown by enhancing electric field. The electric field enhancement is realized through two metal pins placed parallel to the field polarization direction in the middle of the waveguide, and air breakdown can be gotten by adjusting the power of the microwave source and the distance between the two metal pins. The experimental principle and corresponding diagnostic method are introduced. Air breakdown experiments have been conducted under 0.1 MPa with 2.86 GHz microwave of 180 ns pulse duration. The results derived agree with theoretical design, validating the feasibility of the experimental scheme.