The invention provides a realizing device of a large-capacitance self-healing optical fiber sensing network based on a light spectrum type optical fiber sensor and a realizing method. The device comprises a light source, wherein the light transmitted from the light source sequentially passes through a coupler, n layers of sensing subnetworks, a wave length converter, a work optical fiber, a wavelength division multiplexer, an optical fiber, a receiving demodulator and a computer; and Maxn=the total energy of the light source / the energy required by each layer of sensing subnetwork. The invention is additively provided with a spare optical fiber and a cross connector in the network, thereby guaranteeing that the optical fiber sensing network can normally work when an optical fiber link goes wrong, so that the network has survivability. The number of sensors multiplexed by the sensing network is the sum of each layer of sensor, wherein, if each layer has k sensors, the number of the sensors is k*n. Maxk=the gross spectrum width of the light source / scanning resolution, thereby greatly expanding the capacitance of the sensing network. The light spectrum of the broadband light source is divided into m sections, Maxm=the gross spectrum width of the light source / the scanning resolution, the m sections are simultaneously scanned, and the scanning time can be shortened at the 1 / m of the original time, thereby improving the sensing speed of the sensing network.