The Dynamic Vehicle Routing Problem with Time Windows(DVRPTW) is broken down into a series of delaying snapshots based on event-trigger. And a dynamic model of DRPTW is established based on these snapshots. An improved large neighborhood search algorithm with double buffers is presented to solve the problem. The algorithm can implement that the latest requests are inserted steady. Computational results of a large number of test problems,which are cited from Solomon's static benchmarks and Lacker's dynamic d...