Abstract: By the classical method of strength of material, thedeformation of carbon-tube nanosprings (CTNS), including cylindrical, conicaland looped ones, under axial-compression, is analyzed, and a generalformula for stiffness of CTNSs is obtained. In order to validate theformula, the stiffness for a cylindrical CTNS is calculated and compared with the corresponding experimental and FE(Finite element) results. It is shown that the present value ofthe stiffness is very close to both experimental and FE ones.