Based on the integrating sphere traced from NIST (U.S.A),a sphere calibration method and protocol for the China Aerosol Remote Sensing NETwork (CARSNET) Cimel sunphotometer was established.Four Ce-318 sunphotometers have been verified using the calibration method and operational protocol.The calibration results show the instruments coefficients differ less than 3% (~5%) for visible ()(infrared) wavelengths from the original ones offered by Cimel Co.Ltd.In-situ validation experiments data showed the irradiances at ±6° measured by sun collimator (aureole) are consistent with those measured by sky collimator (sky) under both almucantar (ALMUC) and principal plane (PPLAN) scenarios.The differences at all wavelengths are less than 1%,which indicates the method and protocol are suitable for CARSNET field sunphotometer calibration and should benefit the improvement of data quality and accuracy of network observations.