A method for controlling transmit power of a preamble sequence by a Subscriber Station in an Orthogonal Frequency Division Multiple Access communication system, the system dividing an entire frequency band into a plurality of sub-carrier bands, transmitting an preamble sequence for an Adaptive Antenna System through a predetermined number of sub-carrier bands from among the sub-carrier bands, transmitting a data symbol through remaining sub-carrier bands excluding the sub-carrier bands used for transmitting the preamble sequence. The method includes determining the transmit power used for transmitting the data symbol; and determining the transmit power used for transmitting the preamble sequence to be identical to a preset threshold transmit power when the transmit power of the data symbol is smaller than the threshold transmit power, and determining the transmit power used for transmitting the preamble sequence to be identical to the transmit power of the data symbol when the transmit power of the data symbol exceeds the threshold transmit power.