A data transmission method is applied to a primary base station and includes: when configuring a secondary base station for a terminal, configuring, for the secondary base station, carrier parameters for use by the secondary base station; configuring, for the terminal, an autonomous denial rule used when cross-modulation interference occurs between carriers for use by the secondary base station and a carrier used by the primary base station; sending the carrier parameters and the autonomous denial rule to the terminal so that the terminal determines a carrier used by the secondary base station according to the carrier parameters, determines autonomously denied carriers according to the autonomous denial rule when cross-modulation interference occurs between the carrier used by the secondary base station and the carrier used by the primary base station, and performs data transmission by using carriers other than the autonomously denied carriers.