In this paper, the MODIS (Moderate Resolution Imaging Spectroradiometer) data taken on Aqua and Terra satellites, GOES infrared satellite cloud imagery provided by NASA , ERA5 data from ECMWF (European Centre for Medium-Range Weather Forecasts, hourly time interval and horizontal resolution 0.25°×0.25°) were used to analyze the fundamental features and geographical distribution of Actinoform Clouds over the Pacific Ocean from 2012 to 2016. The results showed that most of Actinoform Clouds exhibited “circular” or “elliptical” shape, with obvious center of cloud system and clear “radical arms” extending from the center to outside, which looked like a “wheel” in ancient times. About 85% of Actinoform Clouds occurred over the Southern Hemisphere, and the vast majority of them occurring over the Southeast Pacific Ocean off the coast of Peru. Actinoform clouds occurred all the year round except for February. The high occurrence frequency months are June, July, and August, respectively. The middle occurrence frequency months are May, September, and October, respectively. The low occurrence frequency months are January, February, March, April, November, and December, respectively. The atmospheric inversion layer had important effect on the formation and dissipation of the Actinoform Clouds. The interior of the cloud system was dominated by upward motion. Some of Actinoform Clouds exhibited rotation patterns. The upward and downward motions of the water vapor affected the structure of cloud system.