1. A method for a sign language translation and descriptive video service, the method comprising: extracting a character string in a text form from a caption of an original video; translating the character string to a machine language by: separating the character string based on a word space and a sentence identification symbol, separating the separated character string into morpheme units, and translating morpheme units to the machine language; matching the machine language with a sign language video in a database; and synchronizing the original video with the sign language video, and mixing the original video and the synchronized sign language video.