Abstract: During the process of object positioning, the vehicle electro-optical reconnaissance system needs to establish a series of coordinate systems, such as electro-optical platform coordinate system, inertial guidance coordinate system, local coordinate system, geocentric coordinates and the reference ellipsoid based longitude and latitude representation coordinates. Considering the differences of operation mode and mounting position of electro-optical platform and inertial guidance system, the object position model was derived, the longitude, latitude and height were calculated, and the accurate positioning of object was realized. The main error sources of electro-optical system were analyzed and experimentally simulated through the model, the result shows that the model meets the precision requirement of object positioning. The result of system field test shows that the object positioning accuracy is better than 15 m.