Currently, the urban landscape ecological risk assessment research lacks a reasonable and reliable evaluation framework. Based on the paradigm of landscape ecological risk assessment, the authors clarified the calculation method of urban landscape ecological service value, analyzed the natural and artificial factors that cause ecological damage, and formed the technical framework and parameter system of urban landscape ecological risk assessment. The Tiantan Park (Heaven Temple) region of Beijing was selected as a case study region and a quantitative assessment was carried out. The results show that (1) the total landscape ecological value of the Tiantan region is about 241 million yuan. The history & culture value is the highest, followed by the education and aesthetic landscape values. (2) The probability of urban landscape ecological damage shows a spatial distribution pattern that the high-value region lies in the north while the low-value region in the south. The high probability area accounts for 22.2% of the total area, which is mainly distributed near Zhushikou, Ciqikou, and Chongwenmen. (3) The urban landscape ecological risk presents a spatial distribution pattern that the low-value region lies in the north and the high-value region in the south. The high ecological risk region is mainly distributed around the cultural relic buildings in Tiantan Park. This study provides a reference application framework for urban landscape ecological risk assessment, and discusses the main uncertainties in assessment research. The specific conclusions about the Tiantan case area may help city managers avoid potential risks.