Abstract: A rigorous geometric processing model for ZY-3satellite images based on image-forming principles for three-line array sensors equipped in ZY-3was built using satellite statedata such as the line-of-sight angle.The validation results show that positional accuracy wasnot good when satellite state data and a rigorous geometric processing model was directly ap-plied without processing.This was caused by errors created when obtaining satellite statedata such as the line-of-sight angle and sensor position.In order to decrease original systemerrors in satellite orbital position and attitude angles,a modified model based on the line-of-sight vector was introduced to modify these system errors.After the processing,positonalaccuracy in flat areas was more precise than 3meters even when only 3control points wereincluded in x-y directions.