The static error of the fiber optic gyroscope north-finder includes the drift of gyroscope, incline measurement error, mounting error, position transformation error, and physical quantity error etc. The impact of the various errors on the accuracy of the four- position north-finder was analyzed, and the error model was derived specially, and the simulation was carried out based on the study above. Simulation result indicates that the most important impact fact is the precision of the gyroscope, and the influence of the position transformation error and mounting error both are bigger than that of the incline measurement error. It also suggests that the influence of all the error except the mounting error will become serious if the latitude goes high. In the end, the advisable scheme to improve the accuracy of the four- position north-finder is put forward.