The optical devices of angle-information transfer system were designed by use of the electro-optic effect of LiNbO_3,and a minimum 2.5-second angle variation can be detected with this system.The set-up is made up of a transmitting set and a receiving set.The transmitting set is composed of a LiNbO_3 crystal placed between a polarizer and a quarter-wave plate,and a laser diode(LD).The receiviing set consists of a Wollasidon prism and two photoconductive detectors.We have deduced the relationship between the intensity difference of the outgoing beams (ordinary beam and extraordinary beam) and the relative angle of the transmitting set and the receiving set.The effects of position errors of the optical devices on the characteristic of the angle-information transfer system are investigated.The relevant experiments are carried out and the results agree with our theoretical calculations.