An online video and audio editing method and system can create edited final products by performing video and audio editing via a communication network. The system includes a server, which provides downloadable operator interface software; and a client terminal, which is connected with the server via a communication network. The client terminal downloads the operator interface software from the server to allow selection of target files, and generation of an editing result file by recording the editing information of each selected target file in a text format. The editing information is transmitted back to the server, and includes a priority order, a time to start playback, and a playback length of each selected target file. The server synthesizes all target files in accordance with the editing result file to create the edited final product.