The invention discloses a novel low profile electric scanning beam reflective array antenna comprising multiple reflective array antenna subarrays, a phase shift switching waveguide system, a bias voltage circuit, a beam control device and a power supply. The multiple reflective array antenna subarrays are arranged in parallel. The reflective array antenna subarrays comprise a reconfigurable reflective array plane, a polarized grid leaky wave structure, a first CTS feed structure and a second CTS feed structure. The reconfigurable reflective array plane is connected with the polarized grid leaky wave structure. The reconfigurable reflective array plane is arranged on the polarized grid leaky wave structure. The first CTS feed structure is connected with one end of the polarized grid leaky wave structure. The second CTS feed structure is connected with the other end of the polarized grid leaky wave structure. The phase shift switching waveguide system is connected with the first CTS feed structure and the second CTS feed structure. The problem of leaky wave feed excitation design of the large aperture antenna array plane can be solved and the multimode work capacity can be provided.