A digital sensor for pre-warning of multistage breakage-triggered deformation threshold includes first tension rods, second tension rods, an RFID chip, and a brittle fracture module; the brittle fracture module includes a bottom plate and a plurality of resistors, where two ends of the bottom plate are fixed to the first and second tension rods, and the plurality of resistors forming a lumped parallel circuit are parallelly arranged on the bottom plate; the RFID chip is connected to two ends of the lumped parallel circuit. Strength of the middle cross section of the bottom plate is reduced in the way. The bottom plate will be fractured by being tensioned when the first tension rods and the second tension rods move away from each other with the deformation of the tension members. The resistors are connected into the lumped parallel circuit through brittle wires with different preset slack amounts.