An amplifying circuit and a rectifying antenna are provided. The amplifying circuit includes: a first rectifying circuit, configured to output a first direct current signal according to a first alternating current signal; a second rectifying circuit, configured to output a second direct current signal according to a second alternating current signal; a differential amplifying circuit, configured to receive the first direct current signal and the second direct current signal, amplify a difference between the first direct current signal and the second direct current signal, and output an amplified difference between the first direction current signal and the second direct current, the first direct current signal and the second direct current signal have directions opposite to each other.