A method for transmitting HARQ-ACK information based on transmission diversity is provided. The method includes configuring two component carriers, referred to as Cells, for a User Equipment (UE); when a base station configures the UE to transmitHARQ-ACK information adopting the transmission diversity technique, the base station indicates dynamically whether an other Cell is scheduled in the same subframe via a PDCCH scheduling a PDSCH of one Cell, so as to enable the UE to know the number of Cells scheduled in the same downlink subframe by the base station, and to generate HARQ-ACK information based on the number of Cells. Unnecessary spatial bundling of the HARQ-ACK information may be avoided, unnecessary downlink data retransmission is reduced and throughput of downlink data is improved.