Sealing device and valve body system

The invention discloses a sealing device and a valve body system. The sealing device comprises a driving part, a sealing body and an expansion part; the sealing body is suitable for being mounted on a shell body, the sealing body is provided with a mounting hole, the mounting hole is suitable for being matched with a to-be-sealed pipe body, and the sealing body is provided with a mounting cavity; the expansion part is mounted in the mounting cavity and provided with an expansion cavity, and the driving part communicates with the expansion cavity; and the expansion piece has the expansion state that the area of the expansion cavity is expanded to drive the sealing body to deform towards one side of the to-be-sealed pipe body in the radial direction of the mounting hole under driving of the driving part, the sealing pressure of the sealing body on the to-be-sealed pipe body is also increased, and it is guaranteed that no leakage is generated at the connecting position of process pipelines in a multi-way valve b