Abstract: The control modes in multi-axial and low- frequency random vibrations are studied in this paper based on the three-axis and six-degree-of-freedom hydraulic vibration system. According to the multi-axial and low- frequency random vibration control theory, six control modes are designed, with the control points under the table, on the table, on the fixture, and in other arrangements, respectively. The calculation method of the conversion matrix and the rotation conditions in each control mode are presented in detail. The test results show that the different positions of control points, combined with different conversion matrices and rotation conditions, can be selected to realize various loading conditions, which can serve as a reference for parameter setting in multi-axial and low-frequency vibration tests.