To meet the requirements of large-scale hyperspectral image analysis and identification applications, a processing flow of georeferenced mosaic is set up particularly for Hyperion true color images with overlapping areas. The method mainly includes algorithms of brightness balancing and cutline feathering. Advanced weight-smoothing is applied to blend image boundaries as a feathering technique, and brightness balancing is fulfilled using Improved-Compensation and Histogram Matching. In these improved methods gray threshold is setting extra for features of Hyperion data, which include random high brightness factor (e.g. cloud and mist). Furthermore, all these methods are easily operated and quite effective for massive data such as Hypeiron images. Finally, a mosaic thematic map (with a scale of 1:100,000) of 8 scenes of Hyperion images is produced based on the research in this paper, which makes the image boundaries natural and provides a good visual result.