Taking the Dalian City as the research area, based on the GIS technology, the analytic hierarchy process (AHP) and entropy weight method (EWM) were introduced to evaluate the comprehensive risk of rainstorm-flood disaster by using the daily precipitation data and socio-economic data of the Dalian City. 18 indicators in the risk assessment of rainstorm-flood disaster were selected to build the comprehensive risk assessment model of rainstorm-flood disaster in Dalian City from four factors, consisting of the hazard, exposure, vulnerability and emergency response & recover capability. The results of comprehensive risk assessment showed that the spatial hazard distribution of rainstorm-flood disaster in Dalian City has the characteristics of being higher in the northeast and southwest and lower in the middle. The exposure and emergency response & recover capability of rainstorm-flood disaster were lower in the northern Dalian, but higher in the southern Dalian. The vulnerability of rainstorm-flood disaster was higher in the southwest and central Dalian, while that was lower in the northeast and southern Dalian. The comprehensive risk grades of rainstorm-flood disaster in Dalian City were mainly medium risk, accounting for 41.3% of the whole study area, and they were distributed in patches from the northeast to the southwest. The low risk areas, accounting for 20.93% of the total area, were mainly distributed in the northwest of Zhuanghe and Wafangdian, while the high-risk areas were small, only accounting for 0.72% of the whole area, in the Shahekou District and the Changhai County. As the high-risk areas of rainstorm-flood disaster in Dalian City, they are extremely likely to encounter the flood disaster under extreme rainstorm conditions and have become key areas for the flood control with more attentions.