Under complex stress path including principal stress rotation, the research on remolded soft clay mechanical characteristics needs to improve its reliability, because the large volume’s method of specimen preparation reduces the physical balance and coring operation disturbances the sample. Based on vacuum preloading technology, a new kind of device and method is designed to prepare remolded specimen. The core component is the vertical drain body, which has a dual role of drainage and the inner wall molding. The important technology includes gradation loading of vacuum preloading and simultaneously preparing multiple samples. The method can prepare multiple hollow cylinder specimens quickly; the specimen’s moisture is better uniformity and consistency. This method can reduce the disturbance of the specimen of late coring operation. The verification tests is carried out under principal stress rotation path. The specimen’s reliability is proved, considering aspects of soil mechanical characteristics, when the specimen is applied to studying the of soil behavior evolution law under complex stress path. The specimen also provides the prerequisite for the static and dynamic mechanical characteristics systematic study and long-term stability of soft clay.