In order to solve the low stability of the axial mechanical face seal at high and low speed, by applying the TRIZ theory and combining with the space separation principle of the physical contradiction, a mechanical seal with an external driving rotating middle ring was designed. A rotating middle ring driven by an external power source was added in the seal face between the rotating ring and static ring in the designed mechanical seal, the active control on the relative speed in the seal face between the rotating ring and static ring was realized. The experimental results show that the mechanical seal with an external driving rotating middle ring improves the sealing stability of high and low speed, meet the sealing requirement of different conditions. The leakage of this mechanical seal is increased, but within the permitted range.