Abstract: With the continuous development of deep oil and gas, minerals, geothermal resources, and other resources, there are increasingly more stringent requirements for equipment. In particular, the ultra-high-pressure dynamic seals of deep mining device need to be developed. Therefore, considering the use of dynamic seals in unique deep mining environments, an ultra-high-pressure rotating combined dynamic seal was designed and developed and its sealing performance was experimentally measured and analyzed. The results show that the experimental device can operate stably under a pressure of up to 150 MPa and a rotating speed of 76 r/min, and can also operate normally under a rotating speed of up to 140 r/min and a sealing pressure of 120 MPa. During the operation of the ultra-high-pressure rotating combined dynamic seal, the sealing ring does not show obvious damage, which vouches for its sealing performance. No leakage of flow and pressure was detected in the all seal structures within the sealing pressure range of 0–150 MPa. Therefore, the dynamic sealing performance of the device is intact under ultra-high-pressure conditions and can be applied in deep mining environments at a certain depth. The research and development of this device can aid future deep energy exploration and exploitation.