An improved differential evolution algorithm called inertial velocity differential evolution(IVDE) is proposed to solve the multiprocessor task scheduling problem(MTSP). The proposed algorithm consists of an additional inertial velocity factor based on the adaptive differential evolution algorithm with different evolution state representation schemes. Three different representations for the state of differential evolution algorithm, processor list(PL), partial ordered task list(PTL), and complete task list(CTL), are proposed for IVDE. Intensive simulation experiments are conducted on different random benchmarks and real-world application graphs. Comparisons are made with the ant colony optimizer(ACO) algorithm and the hybrid GA(TLPLC-GA) algorithm. The experimental results are satisfactory, and in most cases the presented method has a better makespan closer to global minimum compared to related works.