A method and apparatus for transmitting HARQ-ACK information are provided. The method includes: in a CA TDD system, when uplink-downlink configurations of aggregated serving cells are different, and a mode of PUCCH format 1b with channel selection is configured to be used to feed back the HARQ-ACK, determining, according to a timing relationship between the PDSCH and the HARQ-ACK information complied by a secondary serving cell, a set of downlink subframes of aggregated serving cells in a feedback window corresponding to an uplink subframe; and determining, according to the relationship between the sets of downlink subframes of the aggregated serving cells in a feedback window corresponding to uplink subframe, the transmission mode of the HARQ-ACK information of the serving cells and the used PUCCH resources when transmitting the HARQ-ACK information; and on the determined PUCCH resources, transmitting the HARQ-ACK information by using the determined transmission mode of the HARQ-ACK information.