Old residential estates account for over 40 % of the total residential development in 20 major cities in China while the percentage is up to 61 % for Shanghai. Many of these old residential estates are facing the dilemma of the increasing demand for car parking space and the deteriorating outdoor thermal conditions. This paper presents a parametric study on the impact of arranging parking spaces and greening on summertime outdoor thermal conditions (air temperature and physiological equivalent temperature) considering the land and building constraints of old residential estates. Field measurements were conducted in an old residential estate located in the inner-city area of Shanghai to obtain the status-quo parking and greening design and basic thermal condition. The current situation along with 26 practical scenarios with different parking areas and greening designs were simulated using the validated ENVI-met model. Results confirm that adding parking space increases thermal stress and its impact is strongly affected by greening design. The magnitude of temperature reduction caused by the greenery decreases as the parking spaces increase, while multifunctional solutions with parking under large trees have strong potential in improving thermal comfort. Regression was also conducted to quantify the impact of different greenery (large trees, medium trees, small trees, shrubs, and grasses) on the thermal condition.