A microwave oven, comprising: a cooking cavity; a microwave source; a controller, which is connected to the microwave source, for controlling the power of the microwave source; a first isolator for feeding amplified microwaves, into the cooking cavity after passing through the first isolator, which is provided with a first input port, a first output port and a first isolation port, the first input port being connected to the microwave source, the first output port being connected to the cooking cavity, a second isolator for feeding amplified microwaves, that are reversely transmitted by the cooking cavity, into the cooking cavity again by the second isolator, wherein the second isolator is provided with a second input port, a second output port and a second isolation port, and a second feed-in device is further arranged on the cooking cavity; wherein the first isolation port of the first isolator being connected with a load, wherein the load is a resistor, one end of the resistor being electrically connected with the first isolation port via the second isolation port, the other end of the resistor being grounded, a first feed-in device is arranged on the cooking cavity, and the first output port is communicated with the cooking cavity through the first feed-in device; wherein the second input port of the second isolator is connected to the first isolation port, the second output port is communicated with the cooking cavity through the second feed-in device, and one end of the resistor is connected with the second isolation port; characterized in that the microwave oven further comprises a detector, which is connected with the first isolation port of the first isolator, and is configured for detecting microwave signal strength output by the first isolation port and feeding back a detection result to the controller, wherein the detector is further connected with the second input port of the second isolator; wherein the detector comprises a coupler, which is connected with the first isolation port and both the first feed-in device and the second feed-in device are welded or clamped or screwed on the cooking cavity and both are probes or antennas. a cooking cavity; a microwave source; a controller, which is connected to the microwave source, for controlling the power of the microwave source; a first isolator for feeding amplified microwaves, into the cooking cavity after passing through the first isolator, which is provided with a first input port, a first output port and a first isolation port, the first input port being connected to the microwave source, the first output port being connected to the cooking cavity, a second isolator for feeding amplified microwaves, that are reversely transmitted by the cooking cavity, into the cooking cavity again by the second isolator, wherein the second isolator is provided with a second input port, a second output port and a second isolation port, and a second feed-in device is further arranged on the cooking cavity; wherein the first isolation port of the first isolator being connected with a load, wherein the load is a resistor, one end of the resistor being electrically connected with the first isolation port via the second isolation port, the other end of the resistor being grounded, a first feed-in device is arranged on the cooking cavity, and the first output port is communicated with the cooking cavity through the first feed-in device; wherein the second input port of the second isolator is connected to the first isolation port, the second output port is communicated with the cooking cavity through the second feed-in device, and one end of the resistor is connected with the second isolation port; characterized in that the microwave oven further comprises a detector, which is connected with the first isolation port of the first isolator, and is configured for detecting microwave signal strength output by the first isolation port and feeding back a detection result to the controller, wherein the detector is further connected with the second input port of the second isolator; wherein the detector comprises a coupler, which is connected with the first isolation port and both the first feed-in device and the second feed-in device are welded or clamped or screwed on the cooking cavity and both are probes or antennas.