The invention provides a microwave reaction device using a coaxial leaky antenna and application of the microwave reaction device using the coaxial leaky antenna. The device comprises a microwave heating device and a reactor, wherein the microwave heating device comprises a microwave generation and transmission device and the coaxial leaky antenna; the microwave generation and transmission device comprises a microwave power source, an annular device, a false load, a microwave power detection device, a coaxial converter and a microwave tuning device; the coaxial leaky antenna is connected to the coaxial converter, and extends into from any end of the reactor, so that microwaves are fed back into the reactor. The device provided by the invention is high in microwave energy coaxial conversion efficiency, is uniform in microwave distribution in the reactor, can be applied to any reaction for heating by utilizing the microwaves, and is especially suitable for large-scale microwave reaction.