Urban parks can offer a variety of ecosystem services such as beautifying the landscape, ecological regulation, leisure and recreation, and maintaining biodiversity. Understanding how urban parks affect people’s lives can help guide the construction and planning of parks in a direction that is more beneficial to the public. Therefore, it is worth studying the extent to which different urban parks with different characteristics affect public behaviour and preferences. This paper takes five typical urban parks in Chengdu and analyses the relationship between characteristics of the park ecosystem and public behaviour and preferences. The characteristics include the park scale, blue-green space ratio, plant diversity, and degree of re-wilding. Visit frequency, stay time, and park preference characterise public behaviour and preferences. The results show: (1) There are obvious differences in the ecosystem characteristics of the five parks: Qinglong Lake Wetland Park is the largest; the proportion of blue-green space in Jiangjiayiyuan Garden is the highest; the degree of re-wilding in Bailuwan Wetland Park is the highest; the proportion of green space and plant diversity in Guixi Ecological Park is the highest; and the proportion of blue space in Jincheng Lake Wetland Park is the highest. (2) There are differences in public behaviour and preferences for different parks. Tourists visit Qinglong Lake Wetland Park the most in spring and autumn and they choose Guixi Ecological Park instead in summer and winter. The public stays longer in Qinglong Lake Wetland Park and shorter in Jincheng Lake Wetland Park. (3) The scale of urban parks, the proportion of blue-green space, and the degree of re-wilding, especially the proportion of blue space, have a positive impact on the public’s evaluation and promote public visits. The results of the study could help improve public awareness of the relationship between park characteristics and ecological services and well-being.