The present application discloses a method and an apparatus for transmitting a message. The method of an embodiment comprises: dividing a shared memory area allocated by an operating system into a plurality of memory blocks for storing messages having different priorities; dividing each memory block in the plurality of memory blocks into at least one memory unit having a successive serial number; determining, from the plurality of memory blocks according to a priority of a to-be-transmitted message, a target memory block for storing the to-be-transmitted message; and writing the to-be-transmitted message into a memory unit of the target memory block. This embodiment implements message transmission based on priorities of the messages, and improves the control security of an intelligent control system.