Abstract: A heterogeneous network can improve spectral efficiency significantly by deploying some low-power base stations, but it can also bring serious interference; hence, a transmission method with multi-point cooperation is needed to illuminate the interference. A multi-point coordinated transmission method based on space-time block coding-block diagonalization (STBC-BD) is proposed for heterogeneous networks. Multi-user dual-stream transmission is implemented by selecting qualified users and improving a dual-stream beamforming matrix. The dual-stream data of each user is also encoded based on STBC, and the received signal to noise ratio performance is improved. Furthermore, a STBC-BD decoding algorithm based on successive interference cancelation (SIC) is designed to further reduce the error rate. According to the simulation, using the STBC-BD algorithm, users' bit error rate (BER) is decreased by 3.5 dB in the 4×4 antenna configuration. Compared with the minimum mean square error decoding algorithm, the proposed STBC-BD SIC algorithm decreases BER by 2 dB.