Objective:To apply theories and techniques of an image bi-valuation that we proposed in medical image. Methods: The parameters are chosen by theory and technique for gradually flattening gray/chroma spectrum we proposed

and then the image were converted into bi-valuation image based on the bi-valuation algorithms. This method was compared with Otsu algorithms and the paint software in Windows operation system. Results:The present theories and techniques had better than the function of an image bi-valuation of Otsu algorithms and the paint software in Windows operation system. Conclusion:The theories and techniques for bi-valuating an image with parameters are generalisable.