A random access method for improving scrambling performance is disclosed. In particular, when a terminal performs a random access to a specific network, the present invention proposes a scheme for transmitting an uplink transmission signal corresponding to an uplink grant by scrambling the uplink transmission signal using a terminal identification information value received via a random access response message. Preferably, the terminal identification information value used for the scrambling is able to use a temporary C-RNTI received via the random access response message.