A scheduling algorithm that is based on synthesizing two expectations of the characteristic parameter (e.g., expectation of deadline and expectation of laxity) is presented . In the set of tasks, each character parameter is quantitated by the expectation of the character parameter, and task propriety is assigned by computing the weighted sum of the two quantitated parameters. According to stimulated results, it is shown that the proposed algorithm improves the success ratio and stability of task scheduling. This designed algorithm can be applied to task scheduling in real-time system.