For the energyaware schedule of batterypowered realtime embedded system, a novel offline energyaware schedule algorithm is proposed based on the improved artificial fish school algorithm(IAFSA). The algorithm constructs the behavior constraint of the artificial fish to make the random search meet the energy constraint and deadline while maximizing the system reward. Experimental results show that the proposed algorithm improves the system reward about 47% compared with the Greedy algorithm. Besides, the energy efficiency increases while the energy budget decreases, which demonstrates the good energyawareness efficiency of the proposed algorithm.