A high precision north finder based on rate biased ring laser gyro (RLG) is designed. The north finder is constituted by the 90-type RLG and a high precision one-axis rotation platform. The north finding experiment is realized by using two-position sampling scheme. To weaken the effect of quantification error, moving average method has been carried out. The experiment is carried out at the geography latitude of 28.2°. It is shown that the precision of north finder on stationary base is better than 16″ after 200 s.