A random access method, device, and terminal for an LTE system operating on an unlicensed frequency band. The method comprises: determining a format of a random access preamble sequence; determining, according to the format of the random access preamble sequence, a channel detection mode for a random access channel; performing, according to the determined channel detection mode, detection on the random access channel; and upon detection of the random access channel being in an idle state, sending the random access preamble sequence via the random access channel.