The invention discloses a load modulation circuit for RFID (radio frequency identification). The load modulation circuit comprises a first load modulation module and a second load modulation module which are connected with a coupling circuit, wherein the load modulation is mainly finished by the first load modulation module under low field intensity, and the contribution of the second load modulation module to load modulation waveform and load modulation depth is far smaller than that of the first load modulation module; with increase of the field intensity, the contribution of the first load modulation module to load modulation waveform and load modulation depth is reduced gradually, and the contribution of the second load modulation module to load modulation waveform and load modulation depth is increased gradually under control of variable voltage; and the load modulation is mainly finished by the second load modulation module under high field intensity. The load modulation waveform and load modulation depth under high field intensity can be better improved, the compatibility of an RFID card can be improved, and normal communication between the RFID card and a card reader is guaranteed.