The invention discloses a displacement dimension measuring device for measuring the displacement of a movable contact and a spring bracket of a vacuum circuit breaker. The displacement dimension measuring device comprises a hollow sleeve, a probe arranged inside the hollow sleeve, a first displacement sensor, and a second displacement sensor. The probe is capable of sliding in an axial direction in the hollow sleeve; the first end of the hollow sleeve is able to be fixed relative to the spring bracket; and the first end of the probe is abutted against the movement contact all the time. A transmission rod of the first displacement sensor is fixed relative to the second end of the hollow sleeve. A transmission rod of the second displacement sensor is connected to the second end of the probe and the second displacement sensor is capable of measuring the displacement of the probe. On the basis of the structural design of the displacement dimension measuring device, problems of low measuring precision and low efficiency can be solved effectively.