Both traffic accident reconstruction and responsibility confirmation of traffic accident depend on crash scene diagramming and crash simulation. However, mistakenly recorded road geometry of the crash scene usually causes misunderstandings in the crash scene diagramming and thus the result of accident reconstruction is untrustworthy. Research has thus been continuously done to solve the problem. This study proposed a Google Map-based accident reconstruction system integrating functions of crash scene diagrammingand crash simulation. The modulus of crash scene diagramming includes positioning of accident location, Google satellite map and Google Sketch Up to accurately present road geometry and accident vehicle position information. The modulus of crash simulation refers to the vehicle dynamic differential equations generated using the Newton-Euler formulation, and enhances with the calculation of momentum conservation in the collision to predict the vehicle dynamics after collision. The system developed in this study was validated using a real case. The results showed that a crash scene diagramming correctly drawn on the Google satellite map was an ideal platform to present the crush simulation, and help people understand or make a judgment for accident authentication. Key words: Accident reconstruction, Google map, crash scene diagramming, crash simulation.