The characteristics of mobile communication in rectilinear orbit is analyzed in detail.A rectilinear mobile optical communication system is developed by use of a two-way transmitter and receiver.The basic principle of this system is described.The system is made of the semiconductor laser transmitter at 1 550 nm,high sensitive PIN photo-detector,single spherical lens optical transmitting antenna and solid optical taper coupled optical receiving antenna,etc.The experimental results show that the frame loss ra...