A method and a system for transmitting data are disclosed. A method embodiment comprises: acquiring a most recent shared memory block index of a shared memory segment by a data receiver, the shared memory segment being used by a data transmitter and the data receiver to transmit data; deciding whether the most recent shared memory block index is consistent with a shared memory block index corresponding to data recently read by the data receiver; and determining, according to the decision, whether to read the data in the shared memory block corresponding to the most recent shared memory block index, where the determining includes reading the data in the shared memory block corresponding to the most recent shared memory block index when the decision indicates that the most recent shared memory block index is inconsistent with the shared memory block index corresponding to the data recently read by the data receiver.