Modulation technology is a key technology to improve the performance of visible light communication (VLC) system. The fragility of high-speed LED visible light communication links and inter-symbol interference caused by multipath effect seriously affect the VLC system performance. To solve this problem, the various optical orthogonal frequency division multiplexing (O-OFDM) modulation technologies are proposed. An overview of O-OFDM modulation technologies is summarized and the proposed modulation technologies are classified into four types according to their modulation strategies. Taking different modulation technologies as examples, these strategies are used to analyze the mechanism and the VLC communication performance. In the end, the next step of work is prospected.