The performance of a parallel simulation system depends very much on partitioning simulation workload evenly among the set of processors in the computing environment to ensure load-balance between processors. Most parallel simulation systems employ user-defined static partitioning. However, static partitioning requires in-depth domain knowledge of the specific simulation model in study. It is not effective if the workload of a simulation model could not be quantified accurately or changes over time during a simulation run.Dynamic load-balancing allows the simulation system to automatically balance the workload of different simulation models without user's input. In this paper, the use of dynamic load-balancing in the context of BSP Time Warp optimistic protocol is examined. Based on the BSP cost model, a dynamic load-balancing algorithm for the BSP Time Warp protocol is developed. Using different simulation models, we show that to achieve consistent performance, the dynamic load-balancing algorithm for BSP Time Warp needs to consider both computation and communication workload, as well as lookaheads between processors.