In recent years, flooding in urban areas has emerged as a critical concern globally. Urban flooding ranks among the most devastating natural events and represents a significant issue in many parts of the world. Given the accelerating pace of climate change, the imperative to study disaster management in urban areas has grown significantly. The tolerance of urban areas during flooding events is attributed to gray infrastructure (GYI), a technique employed by urban cities to mitigate natural disasters. However, when GYI reaches its threshold, it becomes less effective, which may lead to an overflow in residential areas. To address this, there is a growing interest in combining GYI with Green Infrastructure (GI) called hybrid infrastructure. GI is a nature-based effort of natural and semi-natural areas that help reduce flood damage. One example of urban GI is urban green spaces (UGS). However, not enough studies concerning its functionality for disaster management have been investigated. This study aims to analyze the contributions of UGS for flood mitigation in urban areas. This research tested the municipalities of Akiruno City, Hachioji City, and Machida City in Tokyo. Flood occurrence and flood damage data from 2014 to 2019 was collected from government statistics. The first analysis conducted was an occurrence analysis, where a logistic regression model was employed. Results showed that UGS have no mitigation effects for flood occurrence. This is because while UGS may help reduce flood damage, they may not directly prevent the occurrence of floods as it is often determined by other factors. The second analysis examined spatial flood damage, using the damaged area as the independent variable. Results showed that there is negative correlation between damaged area and UGS, suggesting that an increase in UGS reduces flood damage. This aligns with the general expectation of the flood mitigation function of UGS. To further investigate this relationship, the edge-to-area ratio (EAR) of each UGS was analyzed to determine whether patches or compact UGS provide better flood mitigation. A higher EAR corresponds to small patches of UGS. The results revealed that EAR had a significant negative effect on flood damage, indicating that patches of green spaces were more effective in reducing damage. This finding suggests that scattered green spaces have greater flood mitigation than a large, centralized green space which highlights the importance of urban planning approaches to enhance flood resilience in cities.