A transmitting method of a signal on a random access channel in a wireless communication system is provided, including that a terminal transmits a preamble on the random access channel with a set time length ahead of the end position of an uplink pilot time slot, wherein the length of the preamble is the length of two symbols without a cyclic prefix. Another transmitting method of a signal on a random access channel in a wireless communication system is provided, including that a terminal transmits a cyclic prefix and a preamble on the random access channel with a set time length ahead of the end position of an uplink pilot time slot, wherein the length of the preamble is the length of two symbols without a cyclic prefix. The methods can avoid the interference of the preamble to the data of the uplink subframe, and can improve the coverage area of the random access channel and the work efficiency of the time division duplex system.