Device applicable to levelness measurement of sealing surface of pressurized water reactor pressure vessel and use method

The invention discloses a device applicable to levelness measurement of a sealing surface of a pressurized water reactor pressure vessel and a use method. The device comprises an upper flat plate, a lower flat plate, a dial indicator, a spiral micrometer and a counterweight. The device and the use method are mainly applicable to levelness measurement in a grinding process of the sealing surface ofthe pressurized water reactor pressure vessel. With the characteristics of pure mechanical structure, integrated design, small size, light weight and the like, a spirit level set meets the use requirements in the grinding process of the pressure vessel; an indirect measurement manner is adopted to avoid secondary damage to the ground sealing surface; a measurement manner of the spiral micrometercombined with the dial indicator is adopted, thereby improving the measurement accuracy of the spirit level set, and ensuring the airtightness and safety of a reactor; and a manner of rotating the spiral micrometer instead of