A method and system to evaluate image-guided dental implant treatment plans with error simulation. Error sources contributing to the inaccuracy of implant cases come from impressions, stone models, radiographic guides, CT scan and its image processing, surgical guides, as well as the surgical procedures. They are translated into the deviations between the planned and actual implant positions and orientations. The error simulation is to continuously modify and update treatment plans with the possible deviations so that the treatment plans can be visually evaluated along with other evaluation tools.