The utility model discloses a lid assembly and disassembly tools behind pressure transmitter makes things convenient for pressure transmitter's maintenance, improves work efficiency. This instrument includes chuck and handle, and the handle is installed on the chuck, and the up end at the chuck is fixed to the fixture block. This instrument simple structure, it is workable, low cost, convenient to use, the dismouting of lid has alleviateed the intensity of labour of pressure transmitter dismouting behind the realization pressure transmitter that can be quick, has improved work efficiency and has protected the production facility simultaneously, has increased the security of dismouting operation.