The invention discloses a multi-user sub-carrier index modulation orthogonal frequency-division multiplexing (SIM-OFDM) transmission method. At a sending end, logic blocking of sub-carriers is carried out by adoption of an orthogonal amplitude modulation order M at first; then, information bits of all users are also grouped correspondingly; each group is divided into two parts again; one part selects one sub-carrier in each block to enable the sub-carrier to be silent; the other part modulates the residual activated sub-carriers in each sub-block; due to inverse fast Fourier transform, parallel-serial conversion and addition of a cyclic prefix, an SIM-OFDM symbol is formed and sent; at a receiving end, logic grouping, which is the same as that at the sending end, of a detection signal output by a GAMP detector is carried out by adoption of a multi-user iterative detection method based on a generalized approximate message transferring algorithm under non-ideal channel state information; a symbol having the minimum power in each group is judged, so that the positions of silent sub-carriers are identified; index bits are recovered; and residual symbols are demodulated, so that digital modulation bits are obtained. By means of the multi-user sub-carrier index modulation orthogonal frequency-division multiplexing (SIM-OFDM) transmission method disclosed by the invention, the energy efficiency and the BER performance are improved.