In order to improve the quality of ocean color satellite remote sensing data and achieve quantitative applications, the accurate calibration of satellite sensor is the key. By using the water and atmospheric optical parameters measured in the South China Sea PY30-1 platform, we have carried out the vicarious calibration of Aqua satellite′s moderate-resolution imaging spectroradiometer (MODIS) sensor by reflectance-based method. Our results show that the calibration gain factor is very close to the MODIS research. In addition to 443 nm band, the calibration gain factor relative deviations were less than 5%. This study shows that the reflectance-based method can be applied to the China Sea, we can get the accurate calibration gain factor.