Image segmentation is one of the fundamental problems in image processing and image analysis.The inherent ill-posedness of image segmentation is the greatest challenge of this research field.Region growing methods are widely used in image segmentation because of their simplicity and efficiency.According to certain major region growing-based segmentation models at present,we summarize the approach of region growing,including seeds selection,homogeneity criterion,applicable condition and improvement direction.Finally,the trend of region growing methods in future is prospected.