Embodiments of the present disclosure relate to the communications field, and provide an information transmission method, apparatus, and system, which can determine a subframe used in enhanced transmission of first information, improving transmission reliability of the first information. The information transmission method includes: determining a subframe for enhanced transmission of first information, where the first information is a master information block, or the first information is a system information block (SIB) including a time division duplex (TDD) configuration, or the first information is an SIB including a multicast-broadcast single-frequency network (MBSFN) subframe configuration; and performing the enhanced transmission of the first information in the determined subframe for the enhanced transmission of the first information.