Disclosed herein is a system and method for estimating an Internet-wide transmission path and transmission delay. The system includes indexing construction means configured to function as storage for storing the results of actual measurement of transmission delay for all destinations on the Internet, and configured to, in order to search for necessary actual measurement results using Autonomous System (AS) numbers, translate IP addresses constituting the actual measurement results into AS numbers and index respective path segments with AS numbers, mapping means for mapping the IP addresses of queried two points to AS numbers, AS path estimation means for estimating an AS path between the two AS numbers, and path stitching means for searching for respective path segments constituting the estimated AS path, stitching the found path segments together and stitching IP paths corresponding to the AS path, thereby obtaining a plurality of stitched paths and corresponding transmission delay.