Expandable convoluted tube technology is based on a special process on round tubing to make the tubing deformed so as to it can smoothly reach the trouble formation through the borehole; then by hydraulic expansion recovery, workover and cementing are realized. This technology has been used in petroleum engineering a lot after its many years’ development, but due to the confinement of the diameter and technology, it has not been applied in geological prospecting with smaller diameter. This paper presents the study that is mainly based on φ75mm small diameter quincuncial shape expandable convoluted tube being made of KP02 seamless steel tube, expansive transformation parameters are obtained by simulation with ANSYS finite element software and indoor experiments, and the contrast and analysis are made on the expanding process.