Abstract: To meet the real-time requirements for query processing over data streams, the deadline is defined as the real-time constraint of continuous queries. A multi-query overload prediction model is thus developed for deadline-aware data stream processing. The overload point predicted by the model indicates the critical conditions under which each and all of the queries can meet the requirements of deadline individually. In the circumstance of multiple queries, the overload point is estimated by finding a query as deadline bottleneck. After processing the deadline bottleneck, the processing capability of the residual queries is just higher than the input stream rate, thus working out the overload point. The simulation results showed that the overload point predicted by the model enables each and all of the queries to meet individually the deadline they required, and that the prediction algorithm is accurate and efficient.