Based on the continuous observation data of the ground-based dual-band all-sky imager (ASC200) from February to May 2019 at the National Integrated Meteorological Observation (Science) Testbed of the China Meteorological Administration in Changsha and the National Basic Weather Station in Baoshan, compared with manual and instrument measurement reference standards, the analysis aims to evaluate the detectability of ASC200 from the three aspects of visible cloud cover, infrared cloud cover and comprehensive cloud cover. The comparison results show that: Samples of comprehensive cloud cover with a difference within ±20% from manual reference standards account for 92.2% at Changsha and 79.4% at Baoshan of the total samples, respectively. Samples of comprehensive cloud cover at Changsha with a difference within ±20% from instrument measurement reference standard cloud cover account for 90.5%, and those with a difference within ±10% account for 86%. The results indicate: (1) Samples of ASC200 comprehensive cloud cover are in good consistency with manual and instrument measurement reference standards; (2) It is verified that the visible cloud observation system is weak in observation under haze or fog weather, and the infrared cloud observation system is weak in cirrus observation; (3) Under the conventional observation conditions with better visibility, the dualband cloud cover observation system is superior to the single band cloud cover observation system.