Optical frequency division multiplexing （OFDM） is an optical communication method which explores optical fiber band and expands the transmission capacity. In recent years

the research in OFDM has made great progress. To decrease the crosstalk and signal distortion

we need to optimize the channel parameters when we design an OFDM system. According to the characteristics of OFDM system

the paper describes a method of time domain analysis

offers the computer numeric solution and stimulates the eye pattern of the received signals. Then

by the eye pattern that illustrates the influence of the parameters on the system performance

the optimized value of the parameters is obtained.