In engineering investigation, geotechnical testing is the main method of obtaining the basic physical parameters of regional engineering geology bodies. Geotechnical testing is a main approach to understand the mechanical properties and the engineering characteristics of earth materials. Hence, many researchers devoted to exploit new techniques or develop new apparatus and devices of geotechnical testing to acquire the accurate data. Among these techniques, 3D printing is a promising technique for improving the apparatus and devices of geotechnical testing. In this article, we designed and developed three experimental devices (the laser water level gage, the vapor saturation ring for the pressure plate apparatus, and the lid of vacuum saturation chamber) by fused deposition modeling (FDM) 3D printing technology to discuss the application and prospect of 3D printing for geotechnical testing. The results indicate that the development time of device can be shorten significantly when the 3D printing technology is applied. Moreover, if FDM 3D printing technology is used to develop devices of geotechnical testing that is under loading conditions, the cracks would be generated between one and another fused filament surface due to the bending deformation, and then the watertightness and the airtightness of devices would not be guaranteed. The work demonstrates that if we understand the principle of 3D printing more clearly, 3D printing is not only an effective technology to develop laboratory or field devices in soil science, geo-engineering, and geotechnical engineering But it also permits a more efficient information and an irreplaceable opportunity to promote the development of experimental soil mechanics.