Green spaces in urban parks provide important ecosystem services. While most of the current research is focused on the ecological environment improvement benefits of green spaces and the microclimate comfort of space, information about the relationship between site spatial characteristics and ecological benefits in cold cities is still limited. In this study, Liming Lake Park in Daqing, China, was selected as the research object. The environmental parameters and site characteristics of green space and adjacent squares were compared, and the role of green space on the improvement of microenvironment quality in the park was investigated. The measurements were conducted in mid-August 2018. The temperature, humidity, noise, wind speed, PM2.5, PM10, and air negative ion concentration of the three plots were measured in the morning, afternoon, and pre-night. The results showed that, in general, the green space in the park could decrease the air temperature, the wind speed, and the airborne particles, while increasing the humidity and the negative ion concentration of the air. The location and space enclosure between green space and square have different influence on the improvement of microclimate quality, as also as the plant structure in the green space. This study provides a reference for the planning and design of similar urban park green spaces.