The surface formed by the influencing of the meteorological disaster event is no more than a polygon in its geometry shape, and the assimilatory meteorological elements, the character of the underlying surface, the habitat and accumulative assets of human beings are all combined on the characteristic influencing dimension of disaster, that the condition indicates significant difference on the distribution and space background somewhere. However, the paper generally implements the spatial analysis and the method of morphology to initialize the digitized dynamical convolution operator, according to the multi-types of land use and land cover represented by the complexity of underlying surface on the urban area. Supported by the combined GIS and the morphology technique, the gridded atlas of the meteorological map is handled by the operation of erosion or dilution. Moreover, with the dynamical erosion and dilation operating to the grid map derived from the map containing the contour lines of these meteorological elements, such as the temperature, the precipitation, the humidity, and any of those observed when the disaster occurred, we could set up the gridded atlas for the urban area influenced by the disaster, and this would be a good way of the meteorological disaster evaluating. The paper takes the research of the high temperature event occurred on 1999-07-22 as a case study, and it shows that the grid which nears or contains the water or green land have been applied with the erosion operating, on the contrary, the grid which mainly made up of building, road, or cement surface, applied with the dilation. The conclusion draw by the paper is conformity with the characteristic of the land surface processing in the urbanized underlying surface, and even the responding behavior is extremely similar. The effectiveness of the case study is very well by applying the spatial evaluating model, and the outcome by the form of atlas is consistent with the actual situation influenced by the disaster. It also demonstrates that the disaster evaluating with the morphological method is easy to operate, and has the ability to deal with the multi-factors that bring about the loss of disaster, which embody the characteristic of the distributing.