Abstract: Airborne three-line CCD Scanner records image and POS data synchronously on fly ,whichis the hot spot of research these days .Linear arrays on the focal plane capture strips of imagery looking forwards ,downwards and
backwards fromthe aircraft .The entire ground surface is imaged three times ,far superior to the 60 % triple coverage in typical fil m-based aerial photography .Because of systemerror of POS a triangulation is required . The first , the imaging Principle of Three-line CCD Scanner has been introduced in this paper and Integrated Sensor Orientation model has been discussed .The second , the paper provides combined block adjustment math models based on Integrated Sensor Orientation model .The remaining misalignment is determined by the combined block adjustment because the axes of the I MUcannot be perfectly aligned with the axes of the sensor system. The offset between the GPS antenna centre and the projection centre must be esti mated also .Finally ,some conclusions are drawn after experiment results are analyzed .In any case ,the Combined Block Adjustment is fully necessary for Airborne Three-line CCD Scanner images .