Objective: To establish an acquisition and analysis method for medical image in the indoor natural light conditions; Method: According to the color characterristics of the medical image and the constancy of supervised color, we make the color codes which are used for a* b* value correction, and gray codes which are used for L* value correction. Then, we carry on topological subdivision to the one-dimensional L* space and the two-dimensional a*b* space respectively. We establish the mapping function "Decomposition-Projection-Restoration", and ran the linear mapping to the one-dimensional L* space and triangle mapping to the two-dimensional a*b* space. We correct the 198 color blocks in 22 pictures Result: Compared with the standard value, Delta L*, Delta C*, Delta E decreased significantly (P<0.01), image's color difference is reduced, color saturation and the value is closer to standard value. Conclusion: TRM(Topology Resolve-Map Model) method can significantly adjust the color error of tongue images under the indoor natural light condition and easy to use, and has a good performance of color correction. It is feasible to apply this method to the color correction of the medical images.