This paper discusses the digitization and utilization of Silk Road old maps created about 100 years ago by M. A. Stein. Firstly we built an environment to browse old maps on Google Earth to improve the usability of old maps. Secondly we created the map of error distribution over Silk Road region, which was revealed by the comparison of old maps with satellite images on Google Earth. Then we tried to explain why these errors were generated by referring to Stein’s own memo written on the time of creating maps. Finally we evaluated the precision of old maps based on these results, and showed them as the annotation of old maps for usage. This leads an information infrastructure to use Stein’s maps for academic research.