Abstract: The integrated ecological environment units are important basis for the implementation of the ecological environment zoning control. The scientific and reasonable delineation and updating of the integrated ecological environment units are the key technical difficulties in improving the ecological environment zoning control system of "Three Lines One Permit". On the basis of sorting out the overall application of the zoning methods for integrated ecological environmental units in all the provinces (autonomous regions and mulicipalities) of China, taking H Province and its three cities A, B, and C as examples, the differences in the results of two zoning methods of element merging method (merging method) and administrative boundary threshold fitting method (fitting method) of integrated ecological environment units were compared and analyzed, the applicability of two zoning methods were discussed under different geographical conditions and ecological environment function characteristics. It was suggested that the merging method should be preferred to delineate the integrated ecological environment units, and the scope and suggestions for the threshold standards in different terrain areas by fitting method were proposed, to provide technical support for optimizing the technical methods of delineating the integrated ecological environment units in "Three Lines One Permit", improving the zoning management and control system of ecological environment, and improving the fine management level and governance ability of ecological environment.