A high-drop air-hole-type photonic crystal ring resonator (PCRR) was proposed based on two-dimensional square lattice configuration. The single mode operation can be realized by compressing the width of bus waveguide. The impact of number of rows of holes on the propagating field intensity distribution was also analyzed. The physical parameters, such as dropping wavelength, dropping efficiency and spectral quality factor (Q) affected by changing the localized refractive index of inner ring and coupling strength between bus waveguide and PCRR, were numerically demonstrated based on two-dimensional (2D) finite-difference time-domain (FDTD) technique. It shows that 99% dropping efficiency and 379 Q can be obtained at 1 528.1 nm signal channel when the width of bus-waveguide and coupling strength are 0.7-periodicity and 0-periodicity, respectively. On the other hand, when the coupling strength increases to 1 periodicity, the Q can be improved by 1 397 with the decreased dropping efficiency by 89%. Besides, the dropping wavelength can be linearly increased with the increase of localized refractive index of inner ring.