The invention belongs to the technical field of optical detection and particularly relates to a multiple-reflection component. The multiple-reflection component comprises a primary mirror and two secondary mirrors; a right-angled reflection mirror is arranged on each of the two sides of the primary mirror; when a reflected light beam deviates from the primary mirror through multiple reflections between the primary mirror and the secondary mirrors, a reflection point on the side of the primary mirror is enabled to deviate by utilizing the characteristic that the right-angled reflecting mirrors can return the deviated light beam in the original direction, so that a group of new reflection paths are formed; through each of the right-angled reflecting mirrors, the light paths are doubled; the light paths are greatly increased through back-and-forth shuttling of an infrared light beam between the primary mirror and the secondary mirror, and the detection requirements of ultra-trace gas can be satisfied.