The invention discloses a frame synchronization method and system for burst OFDM data transmission, and the method comprises the steps that a receiver receives air interface data, carries out the down-conversion, and carries out the filtering of baseband sampling data, and a frame synchronization head of the baseband sampling data comprises a chirp signal and a time domain constant modulus signal.The chirp signal comprises an upper chirp signal and a lower chirp signal. The receiver carries out synchronous search on the chirp signal; and the receiver performs synchronous search on the time domain constant modulus signal. According to the frame synchronization method and system for burst OFDM data transmission, more synchronization head data do not need to be set, the hardware cost does not need to be increased, and the synchronous capture probability requirement and the timing precision requirement of a receiver with the signal-to-noise ratio lower than 0 dB or the wide signal-to-noise ratio working range can be met.