In order to further reduce the volume of the transmitter and receiver of the system, realize high-speed communication, and improve the anti-interference ability of the system, a set of visible light character transmission system based on singlechip microcomputer is designed with STC12 microcontroller as the main control chip. By adopting the line-of-sight link and optical amplitude modulation-direct detection technology, the light-emitting diode(LED) is modulated at high speed, and the anti- environmental noise capability of the system is tested. The experimental results show that the system can realize high-speed data communication of Chinese and English characters within 3 m, with an accuracy of more than 90%. It has good anti-interference performance and easy to carry.