This paper studied the transmission of the athletics starting signal and the end signal detection over the line in track and field competition. At the starting point, 433MHz wireless transmitter module coded and sent the start signal. In the race finish line, the laser device detected athletes signal over the line. The system used an embedded Microsoft Visual Basic 6.0 serial communication control to achieve a reasonable upper and lower computer hardware and software online. Experiments show that: The combination system of hardware and software control applies wireless communication technology and laser detection devices to avoid interference with normal visible light. It has many advantages of a timing accuracy, fast and accurate arrangement of athletes.