The utility model discloses a special detection instrument of locking sleeve, the gas characteristics are: simulate the piece including detecting, the both ends of detecting the simulation piece respectively are provided with the location wall, and the position in the inboard corresponding work piece hole in bottom of detection simulation piece is provided with location structure, and location structure is including center location platform to and center location platform the bilateral symmetry first reference column and the second reference column that distribute, the up end of the up end of first reference column, the up end of second reference column, center location platform and fix a position on the wall that the direction of the corresponding work piece of terminal surface sets up the chamfer respectively. The utility model has the advantages of simple structure, because the position degree and the location structure of symmetry that have set up the location wall that detects the locking sleeve overall length and detected the locking sleeve hole, if locking sleeve on according to the corresponding detection instrument of putting in the position in hole can, therefore its operation is very simple, whether detection locking sleeve that can be quick accurate qualified, detection efficiency is high, the detection error is little.