When 3D modeling are involved in descriptive geometry course teaching of civil engineering, students' learning path are extended. Although the teaching task is increased, teaching contents are enriched. Compared to other modeling tools, Google SketchUp is simple to use, expandable and low-cost. Based on the features, applying Google SketchUp in teaching and interactive teaching of descriptive geometry course by case studies was analyzed. The practice shows that reasonable use of Google SketchUp can effectively strengthen descriptive geometry course teaching effect, improve teaching efficiency, fully mobilize students' enthusiasm in participating in teaching interaction, and improve students' practical ability and the team cooperation.