Microring resonators with different coupling gaps are fabricated by micro-electro-mechanical-systems (MEMS) technology. To acquire the relationships of coupling gap with coupling coefficient and resonance depth, the theoretical analysis, simulation and coupling experiment are carried out. The test results show that, with the increase of the coupling gap, coupling coefficient decreases and coupling depth becomes shallower, which are consistent with simulation. Actual calculation of the coupling efficiency, 3 dB bandwidth and quality factor show that,as the gap increasing, the coupling efficiency becomes lower, 3 dB bandwidth turns narrower and the quality factor increases. The results provide a foundation for further design and optimization of microring resonator and its research and application in related fields.