This paper describes the procedures of reconstructing ancient architecture using solid modeling with geometric analysis, especially the Golden Ratio analysis. In the past the recovery and reconstruction of ruins required bringing together fragments of evidence and vast amount of measurements from archaeological site. Although researchers and scholars in the archaeological field have used traditional manual methods to obtain data, the innovative application of solid modeling and geometric analysis techniques can help verify and reveal unknown or uncertain data. This paper demonstrates application of solid modeling with an approach from geometric construction perspective, along with data collection, literature review and photography analysis. Two case studies are demonstrated in this paper. They are the reconstruction of ruined ancient luxury complex Baths of Caracalla and building of a 3D digital model of Florence Cathedral. In addition, several solid models of case studies are presented in the paper. (Contains 14 figures.)