To apply nano-structured materials in micro/nano system, understanding of the mechanical properties of nano-structured materials is required. In order to perform the mechanical test of nano-structured materials, the mechanical testing system was installed in a scanning electron microscope (SEM). The nano-manipulator was set up in the SEM, and the force sensor formed as a cantilever was mounted on the nano-manipulator. Then, the force sensor can be controlled by using the nano-manipulator. The nano-structured materials were dispersed on the transmission electron microscope (TEM) grid, and both end of the nano-structured materials were welded on the TEM grid and the tip of force sensor by exposing E-beam of the SEM. The tensile tests for carbon nanotubes, ZnO nanorods and ZnS nanowires were carried out in the SEM, respectively. The load response during the mechanical test was obtained by force sensor. The dimension of nano-structured materials was obtained by determining the configuration measured from the TEM. And, strain-stress curve was obtained after mechanical test. The elastic modulus of the nano-structured materials after the tensile tests were calculated and compared. The elastic modulus for multi-walled carbon nanotubes, ZnO nanorod and ZnS nanowire were ~0.98 TPa, ~59 and ~39 GPa, respectively.