Abstract: Abstract: In order to improve the performance of seed tube and solve the problem of bad uniformity of seed spacing caused by unreasonable seed tube structure, this study introduced a method of applying reverse engineering design software Geomagic Design to design seed tube. Reverse engineering is a kind of technology that builds engineering model of products or parts according to prototypes of current products or parts, and then analyzes and improves them. As a new product design method, it plays an important role in absorbing advanced manufacturing technology at home and abroad, shortening product development cycle and reducing production cost. Seed tube is mainly applied in precision planter, which is used to shorten the distance between metering point and dropping point, reduce seed horizontal speed variance between different metering speeds and reduce seed bounce in dropping and falling processes, in order to realize zero-speed dropping seed and make sure of good uniformity of seed spacing. The length of linear part, the angle between linear part and horizontal direction, the curvature of arc part, the central angle of arc part, the cross-sectional area and the smooth degree etc all have significant impact on seed dropping performance. The imported curve-type seed tube was scanned by non-contact laser scanning method of three-coordinate measuring instrument and the three-dimensional (3D) point clouds were obtained. The front and back of the seed tube were scanned respectively in order to get the complete point cloud data; to make the point clouds better matched with the scanned seed tube, unrelated scanned data were deleted through 3D reverse engineering software Geomagic Design, data preprocessing like reducing noise, merging, simplifying, alignment etc. was done, and then the mesh data of seed tube were got. Through the application of 3D reverse engineering software Geomagic Design, based on the mesh data, and by the application features design tools in "design" interface, coordinate system, tube body, semicircle groove, hanger and strip rib and other features were created one by one, and the 3D geometrical model of seed tube was re-built. Error analysis for the re-built 3D geometrical model and the mesh data was done in "measure" interface, and different colors were used to distinguish different errors. If there were large errors, then back to "design" interface and adjust the corresponding features to reduce error and optimize 3D model. The seed tube was trial-produced according to the engineering drawings which were generated from the optimized 3D geometric model. According to the national standard GB/T 20865-2007, the test was done with Fengmei 2BQX-6 corn no-tillage precision seeder, and the performances were compared among the trial seed tube, imported seed tube and without seed tube. Taking the qualified rate of seed number and the no-seed rate in seed channel as the test indices, make a continuous measurement of 100 segments, and the theoretical length of a segment was 250 mm. The results showed that the qualified rates of seed number in seed channel for the trial seed tube, imported seed tube and without seed tube were 95%, 97% and 67% respectively; the no-seed rates in seed channel were 3%, 3% and 33% respectively. It can draw the conclusions that seed tubes can effectively improve seeding quality, and the performance of the trial seed tube is good and equivalent to the imported seed tube. This research can be successfully applied on seed tube design. Applying reverse engineering for designing the seed tube can shorten the design time and reduce the design cost compared with theoretical study and experimental study. The built 3D geometric model provides a certain reference for the improvement and optimization of seed tube.