The present invention provides a signal sending method, device, and system. The method includes: A sender performs signal multiplexing processing on a first service data block in service data blocks to be sent and uplink control information, and performs channel interleaving processing on mixed data generated after the signal multiplexing processing, to generate a mixed data block; the sender performs signal spatial multiplexing processing on the mixed data block and remaining service data blocks in the service data blocks to be sent except the first service data block to generate a spatially multiplexed signal, and then sends the spatially multiplexed signal to a receiver through a PUSCH channel. The present invention solves the problem of signal transmission over the PUSCH channel after a MIMO technique is introduced in an LTE-A system.