The invention discloses a visible light communication system and a visible light communication method based on Turbo codes, relating to the technical field of visible light communications. A transmitting end of the communication system comprises a Turbo code encoding module and an OFDM (Orthogonal Frequency Division Multiplexing) modulation module, and a receiving end comprises an OFDM demodulation module, a decoding iterative control module and a Turbo code decoding module. The communication method comprises the steps of firstly, performing Turbo code encoding and OFDM modulation on a pseudo random sequence and then driving an LED (Light Emitting Diode) light source to produce visible light signals; secondly, converting the visible light signals into electrical signals, dividing the electrical signals into two paths, performing analog-digital conversion and OFDM demodulation on one path, and generating a decoding iterative control signal for the other path according to the intensity of the visible light signals; and finally, decoding the OFDM demodulation signals under the control of the decoding iterative control signal to obtain signal source data. The anti-interference performance of the system is improved by utilizing the encoding gain of the Turbo codes; and the number of decoding iterations can be adjusted in real time according to the change of the signal light intensity, so that the reliability of the system is improved, and the resource overhead of the system is reduced when the receiving threshold of the system is lowered.