The invention relates to the technical field of well testing and logging of an oil-gas field, in particular to a position detector for airtight testing of an oil-gas well. A handle is arranged at one end of a housing of the detector; the housing is internally provided with two connecting conductors; a display instrument is mounted on a side wall of the housing; a coil box II is fixed at one end of the front end of the housing; a coil box I is connected with the other end of the front end of the housing via a pin shaft and can rotate around the pin shaft; the coil box I and the coil box II are designed to be semicircular and is internally provided with metal coils; and the coil box I can be connected and locked with the coil box II to form a closed ring via a locking ring. The detector can precisely detect positions of well testing and logging instruments, is convenient to operate, can protect the well testing and logging instruments well, greatly reduces the possibility of falling of the well testing and logging instruments into a well bottom and collapse of the well testing and logging instruments, increases a logging success rate and has higher economic benefits.