In the design and analysis of discrete event systems, the validation of their models is often addressed via simulation. Petri nets have been applied widely. Lookahead computation is a good method that improves the distributed simulation performance of Timed Transition Petri Nets (TTPN). The approach is based on a part of optimism computed on the prediction time each logical process can determine for its advancement. Timed Petri nets meet these requirements, and use the lookahead to analyze the TTPN model for finding the concurrency and blocking structure, thereby making certain the logical process (LP). Based on the specialties of lookahead, the lookahead was applied in parallel simulation, and acquire the sufficient condition about the TTPN model existing concurrency. According to the condition, parallel program can be partitioned into several logical processes, and the partition algorithm that can decide quickly the mapping project on the mapping process-processor is presented.