A metallic attenuated total reflection GeO_2hollow optical fiber can be very r obust for transmitting a CO_2laser beam because of high toughness and high thermal dissi pation ability of the metal tube.However,the plastic deformation behavior of a metal may cause i rreversible (plastic) deformations as the metallic hollow optical fiber is used to deliver a laser beam. To avoid this,it is necessary to obtain the elastic bending radius of a metalli c hollow fiber and maintain the fiber under an elastic bending condition in practical applicati ons.This work aims to study the elastic bending radius of a metallic GeO_2hollow fiber.The e lastic bending radii are calculated based on the elastic-plastic bending theory of a metal pi pe and the fabrication process parameters of stainless steel or beryllium copper GeO_2hol low fibers.Then, the calculated radii were experimentally investigated.The stainless steel hollo w fiber (internal diameter is 1.4mm,wall thickness is 0.025mm) exhibits elastic bending behav ior when the yield strain is below 0.29%,and the minimum elastic bending radius reaches 249.61mm. The beryllium copper hollow fiber (internal diameter is 1.4mm,and wall thickness is 0.05mm) is elastically bendable as the yield strain is lower than 0.375%,and the minimum elastic bending radius is 199.58mm. The calculated minimal elastic bending radii agree with the measured values of t he stainless steel or beryllium copper hollow optical fibers.