The present invention relates to a pilot allocation method for an orthogonal frequency division multiplexing system, and the said method is used for a communication system which at least includes one transmitter and two transmitting antennas, characterized in including the following steps: step 1, a user data carrier allocating module in the transmitter allocating a data carrier for a user data symbol, then mapping the user data to the allocated carrier, and finally, outputting the mapped user data to a inverse fourier transform module in the transmitter; step 2, at the same time with step 1, the pilot data carrier allocating module in the transmitter determining the allocation rule of the pilot data according to the subchannel allocation manner and the number of the transmitting antenna of the system, and allocating the pilot carriers for the pilot data, then mapping the pilot data to the allocated carriers, and finally, outputting the pilot data to the inverse fourier transform module. The present invention synthetically considers the question of practical application as well as reducing the floor effect.