A method for passive location based on the triangulation principle was studied. By analyzing the ranging precision of dual-station triangulating location system,it proved to be with low precision,and for some target orientations the precision in the target location was completely lost,known as Geometric Dilution of Precision. Combined with the character of the airborne platform,an infrared passive triangulating positioning method applying to a single aircraft was proposed. Four stations were installed in an orthogonal manner on the platform,which constituted two orthogonal triangulation systems. The GDOP can be resolved by selecting the positioning data of the two triangulation systems appropriately. Finally,simulations were also made,whose results show that the method can eliminate the GDOP effect and increase the precision of location.