In consideration of satellite remote sensing quality and precision imbalance at present, and the boundedness brought by using the method of average deviation,standard deviation and etc., this paper puts forward a kind of flexible assessment method which is based on clustering idea that it works into the precision of each point and confidence level changes with the variation of the quality and quantity of information source, which can provides the accurate assessment of variable precision or confidence area of each point, then improves on the quality and precision of the assessment and fusion of SST data.