Abstract: With the advance of the mobile terminals and the wireless communication technology, the number of mobile terminals increases rapidly and these devices are more and more powerful. The appearance of plenty of intelligent devices equipped for short-range wireless communications boosts the fast rise of wireless ad hoc networks application. However, in many realistic application environments, nodes form a disconnected network for most of the time due to nodal mobility, low density, lossy link, etc. Conventional communication model of mobile ad hoc network (MANET) requires at least one path existing from source to destination nodes, which results in communication failure in these scenarios. Opportunistic networks utilize the communication opportunities arising from node movement to forward messages in a hop-by-hop way and implement communications between nodes based on the “store-carry-forward” routing pattern. This networking approach, is totally different from the traditional communication model, captures great interests from researchers. Therefore, it becomes possible to deploy a distributed computing system on these mobile devices as an extension of the traditional one which is mainly composed of computers. We proposed an opportunistic communication based distributed mobile computing mechanism, which is appropriate for those large-scale computing that can be separated into many small subtasks and have a high tolerance of delay. A task is divided into M subtasks by a server at first, then be sent to wireless APs located somewhere through the internet. The mobile terminals (nodes) will download some subtasks while they meet the APs and after the nodes move out of the communication range of the APs, they spray the carried subtasks to some other nodes they meet which don’t take any subtask. The subtasks will be performed until the number of subtasks in a node is 1. The nodes then send results to the APs on opportunistic communication approach and all of results will be sent back to the server. We also discuss some strategies about routing and energy saving.