The utility model provides a time division multiplexing type fiber periphery early-warning system, relating the technical field of mechanism oscillation measurement, impact measurement and pipeline systems. The system comprises a monitoring host (1), a guiding optical cable (2) , a time division switching switch (3) and multiple defense-area optical fibers, wherein the monitoring host (1) is connected with the time division switching switch (3) via the guiding optical fiber (2), and the time division switching switch (3) is connected with the multiple defense-area optical fibers. The amount of the defense-area optical fibers, the amount of required defense areas, and the channel amount of the time-division switching switch (3) are configured according to practical requirements of the defense areas, wherein the channel amount of the time-division switching switch (3) is the Nth power of 2 in cascade or expansion; and amount of cables from the time-division switching switch (3) is taking the length of a first defense-area cable as a radix, and the length of other defense-area optical fibers as a multiple of the radix. The time division multiplexing type fiber periphery early-warning system is high in positioning precision and accurate in positioning positions, and is used in short-distance peripheral defense.