Urban vegetation is a nature-based solution for cooling cities. Under global warming and urban population growth, it is essential to optimize urban vegetation configuration in the urban area to bring maximum cooling benefit. This paper reviews 85 optimized urban vegetation configuration studies published from 2010 to 2020 to provide an insight into the most effective vegetation configuration for urban heat mitigation. Patterns and preferences in methods and the optimized greenery configurations are comprehensively analyzed. The results indicate that size, quantity, and layout of urban green space and the physiological characteristics and spatial arrangement of urban vegetation significantly influence their cooling effect. Additionally, two other research gaps were identified. First, more research needs to be done in southern hemisphere cities experiencing rapid urbanization and severe impacts of extreme weather. Second, a comprehensive method for quantifying interactions and cumulative effects of natural and artificial factors in the urban environment is required. Future study needs a holistic understanding of the interactive effects of vegetation spatial distribution on urban environment and climate for a more accurate analysis of optimal cooling greening layouts in large urban areas at multi-scales.