Traditional single target position finding method can not fit the condition that the situation of modern war field changes in real time and has many targets. In order to enhance the efficiency of target positioning, this paper developed a new semi-active multi-target positioning algorithm for airborne optoelectronic system on the basis of single target position finding. Through establishing the initial east-north-up (ENU) coordinates, aeroplane ENU coordinates, crankshaft coordinates, EO stabilized-aiming coordinates and multi-target projection coordinates, a series of coordinates transform formulas using the relative angles of target were derived, which could calculate the longitudes and latitudes of multi-target. The result of computer emulation showed that this algorithm could calculate the latitudes and longitudes of multi-target at the same time. The positioning precision of hypo-targets was lower than that of the main target because of the increased accumulated error of coordinates transforming by the pixel deviation.