The basic working principle and the two-position north-seeking method based on single-axis FOG(fiber optic gyroscope) is researched in this paper. Improved north-seeking method was proposed to solve the problem in the two-position FOG north-seeking scheme. To Sample in three positions of 0º, 90ºand 180ºseparately and obtain the measurement values of angular rate in these three positions. Then according to the measurement values of angular rate in the first and the third positions to calculate the north-seeking angle, and using the positive and negative pulse outputs of the FOG in the second position to obtain the specific direction information of carrier. So that, accomplish the north-seeking in the range of 0～360° for single-axis FOG. The experiment results showed that the accuracy of the improved two-position north-seeking program based on single-axis FOG is 0.101 (1σ) within 4 minutes.