Abstract: Proposes a new image segmentation method based on Tree-Structured Markov Random Field（TS-MRF） and fuzzy Multi-Level Logistic（MLL） model,where fuzziness has been introduced into TS-MRF and the calculation of potential function becomes more meticulous and more precise.Compares with the classical TS-MRF method,the quantitative errors are smaller under the same conditions when the new algorithm is used,while the computational time increases little.More interesting,this method may hint one simple and efficient way to make MRF-based prior（not limited in MLL model） more precise,i.e.making the MRF-based clique changed to be fuzzy clique by using posterior probability.