This paper presents In situ quick repairing of defects inside a telescoping multi-walled carbon nanotubes (MWCNTs) using contact resistance. The defects were inserted and repaired by In situ nanomanipulation technique inside a transmission electron microscope (TEM). The defects were quickly (less than ~0.1 s) repaired by applying a current after contact with electrode. The repairing of defects was confirmed by bending phenomenon under applying forces though nanomanipulation. The proposed method can be used to control the mechanical and electrical properties of telescoping nanotube quickly for nano-devices applications such as nano-sensor, nano-actuator, and so on.