A load modulation circuit for radio frequency identification including a first load modulation module and a second load modulation module connected to a coupling circuit. Under weak field intensity, load modulation is mostly realized by the first load modulation module, with the second load modulation module contributing far less than the first load modulation module as regards to the load modulation waveform and load modulation depth. As field intensity increases, the first load modulation module contributes less and less to the load modulation waveform and load modulation depth. While field intensity increases, the second load modulation module contributes more and more to the load modulation waveform and load modulation depth under the control of a variable voltage. Under strong filed intensity, load modulation is mostly realized by the second load modulation module.
