Method and system for semantic event indexing by analyzing user annotation of digital photos

A method and a system for indexing photos are provided to index the photo's semantic according to circumstance change by analyzing the photos. A method for indexing photos comprises the steps: receiving a plurality of photos and comments from users(S611); picking up common index words by analyzing the comments(S613); detecting circumstance change by analyzing the photos(S615); and indexing the photos according to the circumstance change one the basis of the common index words.