Abstract: Urban public green space is an important health resource. Its role in public health promotion is closely related to the use behavior. Taking small public urban green space (SPUGS) in the center of Chengdu as cases, the article makes quantitative analysis of the use of SPUGS and its main influencing factors and mechanism under the background of high-density city. The descriptive analysis shows that SPUGS is easier to use nearby by people in their daily life, compared to large urban parks. The multivariate logistic regression analysis shows that age, education, income, children under 6 and distance travelled are significantly related to the use frequency, and age, gender and income have bigger impacts on the main motivations for visiting SPUGS. Our further discussion indicates that compared to distance travelled, the influence of motivations shaped by social-demographic factors on use frequency is more obvious. Finally, we put forward several planning and design proposals in response to motivation.