A message transmission method and a device are used to accelerate a random access procedure. The method includes: receiving, by a terminal device, a repetition quantity of an uplink message from a network device, in response to determining that a reference signal receive power (RSRP) range of the terminal device is within an RSRP range corresponding to a signal coverage enhancement level 0, wherein the uplink message comprises a third message of a sequence of messages comprised in a random access attempt; calculating, by the terminal device, transmit power based on a power control parameter for the repetition quantity; and sending, by the terminal device, the uplink message to the network device based on the calculated transmit power.