正交频分复用（OFDM，Orthogonal Frequency Division Multiplexing）是一种多载波数字调制技术，也可以被当作一种复用技术。具有频谱利用率高、抗多径干扰等特点，OFDM系统能够有效地抵抗无线信道带来的影响，例如信道的频率选择性衰落，脉冲噪声和共信道干扰的影响。本文主要介绍了OFDM原理的相关知识。-The Orthogonal Frequency Division Multiplexing (OFDM, Orthogonal Frequency Division Multiplexing) is more than one kind of carrier digital modulation technology, may also treat as one kind of multiplying technology. Has the frequency spectrum use factor high, characteristics and so on anti-multi-diameter disturbance, the OFDM system can resist the influence which effectively the wireless channel brings, for example channel s frequency selectivity declines, impulse noise/pulse noise/pulsive noise and altogether channel disturbance influence. This article mainly introduced the OFDM principle related knowledge.