A data transmission method is provided to expand coverage of a broadcast channel, including: determining, by a base station, a plurality of data blocks carried on N broadcast channels, where an ith broadcast channel in the N broadcast channels corresponds to an ith antenna port (group) in N antenna ports (group); scrambling, by the base station, the data blocks carried on the N broadcast channels, to obtain scrambled code blocks carried on the N broadcast channels; and sending, by the base station on different time resource units by respectively using the N antenna ports, corresponding scrambled code blocks carried on the broadcast channels, or sending, by the base station on different time resource units by respectively using the N antenna port groups, corresponding scrambled code blocks carried on the broadcast channels.