Hole diameter detection apparatus and method

The invention embodiment provides a hole diameter detection apparatus and method. An embodiment of hole diameter detection apparatus comprises: a transmission part including a cylinder fixed on a cylinder fixing block for providing telescopic motion along the measurement shaft, and a coupling shaft connected with the cylinder and a fastening coupling block connected with the coupling shaft; an induction part including a sensor fixing bar fixed on the fastening coupling block, two sensors mounted on the top of the sensor fixing bar on adjustable positions, a spring shielding sheet mounted under the lower sensor, and a spring disposed between the spring shielding sheet and the limiting block in the measurement part; a measurement part including a limiting block, a measurement shaft guide rod fixed on the limiting block, and a measurement shaft which is connected with the measurement shaft guide rod and has a convergent lower end and a round cross section; and a base used for fixing bearing workpiece for measuring. The invention embodiment improves the stability and reliability of the hole diameter measurement, and reduces production cost.