Numerous cities are facing frequent urban floods due to high rates of imperviousness and increasingly extreme rainfall events. The Stormwater Park (SP) is an effective nature-based solution way to alleviate urban flood risk and improves stormwater utilization. This study proposed a block-level perspective to measure the hydrological benefit of the SP case in Nanjing, southern China. After clarifying the land use and surface configuration of the study area, different low-impact development (LID) measures, connection patterns and one terminal retention pond were considered to improve stormwater management. Four scenarios (S1: Predevelopment scenario, S2: decentralized LID development scenario, S3: integrated LID development scenario, S4: integrated LID with terminal retention pond development scenario) are simulated by Stormwater Management Model (SWMM) under long- and short-duration precipitations. The results showed the volume capture ratio of annual rainfall (VCRa) of four scenarios: S4 > S3 > S2 > S1. LID practices can effectively reduce runoff volume as decentralized source control in small- and medium-rainfall events. And S4 can better effectively delay peak discharge time and increases the retention volume. The study provides a block-level scenario comparison to evaluate the hydrological effectiveness of SPs and to facilitate decision-making for implementing urban blue-green infrastructure that retains, detains and infiltrates stormwater.