On the basis of the characteristics of satellite cloud picture, this paper gives one automatic classification method of satellite cloud image:Iterative Self Organizing Data Analysis Techniques Algorithm (ISODATA). The satellite data used are from two channels of GMS 5. One channel is of 10.5-11.5μm, the other is of 0.55-0.9μm. The calculation shows:while the cloud image is classified as surface, high cloud, middle and low cloud, deep cloud, good results have been achieved.