A method is utilized for scheduling sequence of broadcasting data items in an on-demand broadcast system. The system includes a plurality of data items. The method includes receiving a plurality of requests, calculating a request number of the plurality of requests, calculating a waiting time and an accumulated waiting time relative to a current time of each request, calculating a weighted value according to the request number and the accumulative waiting time, and scheduling the sequence of broadcasting the data item of the plurality of requests according to the weighted value.