A terminal structure for superjunction device is disclosed. The terminal structure comprises from inside out at least one P type implantation ring and several P type trench rings formed in an N type epitaxial layer to form alternating P type and N type regions. A channel cut-off ring is formed at the border of the device. The P type implantation ring is formed adjacent to the active area of the device and covers at least one trench ring. A terminal dielectric layer is formed to cover the P type implantation ring and the trench rings. A plurality of field plates are formed above the terminal dielectric layer. Methods of manufacturing terminal structure are also disclosed.