The invention provides a device for measuring the moisture content of a corn ear based on a standing-wave ratio principle. The device comprises a high-frequency signal generator, a lumped parameter transmission line, two detection rings, two detection circuits and a signal amplification circuit, wherein the high-frequency signal generator is connected with the two detection rings through the lumped parameter transmission line; an input end of one detection circuit is connected with an output end of the high-frequency signal generator and the other detection circuit is connected with the output end of the lumped parameter transmission line; and the input end of the signal amplifying circuit is connected with the two detection circuits separately. The method for measuring the moisture content of the corn ear based on the standing-wave ratio principle is simple in structure, low in production cost, high in measurement accuracy and convenient to apply and popularize, and quick and accurate measurement of the moisture content of the corn ear can be achieved without damaging the corn ear.