In this paper, we present a micro-displacement sensor formed by the fixed and movable photonic crystal slabs. In this sensor, a waveguide was created by changing the radius of holes rather than removing them. At a proper operating wavelength, the structure could be used as the micro-displacement sensor. The results revealed that the micro-displacement sensor had a sensitivity of 3.6 μm-1, the Q-factor was nearly 180, and the sensing range was 0.0 μm-0.5 μm. The properties of the micro-displacement sensor are also analyzed theoretically and verified using the finite-difference time-domain (FDTD) method carried out using the software (Rsoft).