For the purpose of evaluation of the characteristics of the infrared wireless communication channel, the mathematical equations of the impulse response and time delay of infrared channel were defined. The diffuse characteristics of the surfaces of the room were described by Lambertian law.The magnitudes of light of sight and diffuse response of channel, the characteristics of several channels were analyzed and simulated. The results demonstrated that the change of FOV and the change of the position of receiver have serious effects to the characteristics of the channel. The methods of this paper are contributed to the design of a robust infrared communication channel.