The invention discloses a preamble sending method for an orthogonal frequency division multiplexing system, which comprises the following steps: Step S102, a message which needs to be sent to a terminal side is confirmed; Step S104, a first preamble symbol is confirmed according to the message; and Step S106, a base station side sends the first preamble symbol and a second preamble symbol to the terminal side. With the method of the invention, the receiving end greatly reduces the times of the search and obtains more information at the same time.