A string vibration type sensor with digital memory for detecting the broken transmission line and teletransmission of the measured physical parameters has a sealed casing, in which there is a stretched steel string and a permanent magnet and an induction coil symmtrically arranged at both side of said steel string. When a test pulse is input to the coil, it generates an exciting force to make steel string vibrate unidirectionally. The AC signals generated by steel string which is cutting magnetic force lines are processed by processor which is composed of AC amplifier, single-chip processor, serial memory chip and serial interface chip.