A structure of an optical accelerometer based on an optical single ring resonator located onto the cantilever is proposed to meet the requirements of microminiaturization and economical applications in the present paper. The spectra of out port are obtained using transfer matrix method and theory of coupled modes. According to the measurement of intensity of drop port at the same wavelength, the influences of different structure parameters on the sensitivity of the whole acceleration sensor are analyzed. The results show that the cantilever length and thickness and the ring resonator position are all key factors which can influence the sensing property of acceleration sensor. Hence the sensitivity can be effectively improved by adjusting the factors mentioned above. The sensitivity reaches up to 2.112 g-1 and the limit of detection can achieve 1.421 10-3 at 1.515 μm with a cantilever of 180 μm in length and 3 in thickness for a 30 dB signal-noise system. Such structure has great potential to develop low-cost and easy made high sensitive acceleration meter.