In recent years, heavy rain in Surabaya has caused flooding in some area for example in the Dukuh Kupang sub-district. The height of the flood was up to an adult's waist. The Surabaya City Government has made improvements to prevent flooding at several flood points, for example building embankments in Dukung Kupang, widening water channels at several points and improving the performance of officers at pump houses, especially when it rains. Apart from that, there is a need to map areas that are at risk of flooding so that it is hoped that Surabaya will not experience flooding in the future. One technology that can help to map flood hazard areas is the Geographic Information System (GIS). This research uses several parameters, namely rainfall data, elevation data, distance data from rivers, soil type data, slope data, and land cover data. This data has different parameter weights. The research results show that areas with a high level of flood danger in Surabaya reached 40.10%, the areas are Tandes sub-district, Tegal Sari sub-district, Dukuh Pakis sub-district, Mulyorejo sub-district and many more. Research data shows that the distribution of flood hazards is evenly distributed throughout Surabaya sub-districts, this becomes a threat to Surabaya when heavy rain falls. There is a need for activities to clean water channels, especially sediment or mud that has settled. This is expected to reduce the area affected by flooding in the future.