This study uses a rain garden in a certain city as a case study and analyzes its hydrological effects based on the SWMM model. A comparative analysis was conducted between drainage-type (RG-dr) and infiltration-type (RG-inf) rain gardens to explore the impact of different design types of rain gardens on runoff regulation, pollutant reduction, and landscape benefits. The average total pollutant load for the four categories in RG-dr was 56.383 kg, 13.725 kg, 7.484 kg, and 0.904 kg, respectively. The average removal rates for the four categories of pollutants (SS, COD, TN, and TP) were 29.30%, 33.15%, 31.52%, and 39.08%, respectively. Most users considered the landscape effects of RG-dr to be good, with over 50% of users across all age groups rating them as “very good” or “good.” Users generally believed that RG-dr had rich landscape layers, with over 60% of users across all age groups rating them as “very rich” or “relatively rich.”