This paper presents a quantitative image analysis technique for colonoscopy diagnosis to distinguish abnormal lesions, especially for using Fuji Intelligent Chromo Endoscopy (FICE). We take the color histogram technique and gray level co-occurrence matrix (GLCM) into account, and proposed an efficient line-scan method for observing early and small tumor during minute diagnosis. The line-scan method is based on semimanual image horizontal line selection of colonoscopy video, then the color histogram index, contrast, energy, homogeneity and entropy are calculated via GLCM matrix of the selection image area. Thus, the method leads the FICE images measurable and provides a view to accelerate and enhance physician to determine the lesions quickly. The results show that the proposed line-scan method significantly evaluates the diagnosis images for the real patient experiments.