The present invention provides a data transmission method and apparatus. In the data transmission method, a terminal searches for a visible light network and determines a target visible light network from found visible light networks; then obtains a communication parameter of the target visible light network, establishes, according to the obtained communication parameter corresponding to the target visible light network, a downlink VLC link between the terminal and a VLC device corresponding to the target visible light network, and receives data sent by the VLC device by using the downlink VLC link. Therefore, a part of a traffic intensive downlink service is forwarded to the terminal by using the downlink VLC link, and a transmission rate of an entire wireless communications network is increased.