Abstract: As the urbanization accelerates, urban ecological security gradually gains increasingly wider attention. An appropriate evaluation of the city ecological security is of great importance for the making of corresponding regulations and solutions. A case study of Sanming City is made to evaluate its ecological security with fuzzy matter-element evaluation model. The results find a generally rising trend of Sanming's urban ecological security, which sees an increase of approximately 33%, rising from criticality safety to relative safety. This also shows that with the rapid development of Sanming's economy and society, the urban ecological environment problems pop up, and the coordinated development between the environmental protection and the social and economic development is still far from satisfactory, and the conflicts between people and the environment are still wanting a solution.