The utility model relates to a stroke of the telescopic core bar instrument of nuclear power station is measured and is checked technical field, concretely relates to a verification instrument that is used for telescopic core bar instrumental function validity, and the purpose is solved current device can't carry out the measuring problem to telescopic core bar instrument in the reactor body. Its characterized in that, it includes core bar and sleeve, the sleeve suit is in the outside of core bar, sleeve and core bar respectively with telescopic core bar instrument fixed connection. The utility model discloses be applied to fan family mountain nuclear power 1, 2# unit control stick actuating lever chain / instrument check -up before the debugging of unblock instrument, the chain work of initial control rod actuating lever, practice thrift the plenty of time cost, respond well.