Abstract: Based on the analysis of the geological factors influencing the construction of sponge city in Tianjin, We have established the evaluation index system of the geological suitability for the construction of sponge city in the south plain area of Tianjin; AHP method was used to assign the weight of evaluation index for the geological suitability of sponge city construction, than the comprehensive scoring method was used to score the influencing factors, and ARCGIS was used to carry out the weighted superposition of the two, finally realizing the geological suitability zoning of sponge city construction in Tianjin; combined with the overall score, distribution range and regional nature of each district, this paper gives the LID facilities type suitable for the construction of sponge cities in south Tianjin plain area. The results show that the geological suitability of sponge city construction in the central city of Tianjin(including four areas around the city) and the Binhai new area can be divided into four levels:suitable construction area, relatively suitable construction area, general construction area and control construction area, the distribution and properties of each zone are obviously affected by the thickness of the various zone; compared with other cities, the construction suitability zones of sponge city construction in Tianjin are less affected by the topographic slope.