The joint scheduling problem of tasks and network communication is a non-deterministic polynomial hard(NP-hard) problem in the optical grid. In order to further extend the list scheduling, an iterative scheduling algorithm was proposed to optimize the scheduling length. Firstly, an initial task list was sorted according to the priority called bottom level of each task. Then the scheduling order was modified according to the updated time-weight of tasks by estimating the actual communication cost between tasks. The simulation results show that the proposed iterative scheduling algorithm can effectively improve the scheduling length in the majority of the cases, especially for data-intensive applications in task scheduling.