Embodiments of this application provide a random access preamble transmission method and an apparatus. The method includes: obtaining, by a terminal device, a scrambling code sequence, scrambling a random access preamble by using the scrambling code sequence, and sending a scrambled random access preamble to a network device. In this technical solution, the terminal device scrambles the random access preamble, and sends the scrambled random access preamble over a channel, to effectively eliminate inter-cell interference and resolve a possible target cell false alarm problem.