The description for load-displacement characteristics of in vitro spinal specimens in three-dimensional (3D) motion is the foundation of spinal biomechanical research. How to simulate the load and movement of spine in vivo as accurately as possible is the difficulty of in vitro spinal biomechanical research. Domestic and foreign scholars have carried out extensive research on theories and equipments of spinal biomechanical test. Currently, the spinal 3D motion test is mainly divided into load control, displacement control and hybrid control according to the control method. Based on different control method, the test equipments are also developing and perfecting constantly. The operation principle for current in vitro spinal loading devices are summarized, and their advantages and disadvantages are also analyzed, so as to provide references for the research on in vitro spinal biomechanical loading devices.