A novel algorithm is proposed for energy-aware scheduling of periodic tasks on variable voltage processors in the real-time systems. Based on the combined idea of artificial bee colony algorithm with greedy algorithm, different speed is allocated for different tasks to ensure the execution of tasks with higher value density. Simulation results show that the system reward of energy per unit is increased with the decreasing of energy constraint, therefore the scheduling algorithm is of the energy awareness. Compared with the greedy algorithm, the rewards of the real-time system using the greedy artificial bee colony algorithm are averagely improved by 78% while energy constraint factor is 0.1. Mmore system rewards can be obtained with the increasing number of tasks or energy constraints.