The construction of urban ecological security pattern is an important way to ensure regional ecological security and realize sustainable development. Taking Suzhou city as a case, this paper constructs and evaluates the urban ecological security pattern by integrating various methods, such as ecosystem service quantification, ecological security pattern construction and ecological security assessment. The results show that: （1） In 2017, the services of food supply, fresh water supply, air purification, flood regulation and water storage, carbon sink service, tourism and leisure, soil conservation and habitat quality in Suzhou city are 32795.94 yuan/hm2, 686.6 mm, 283.68 yuan/hm2, 28.62 mm, 86.99 t/hm2, 3736.75 yuan/hm2, 174.8 t/hm2 and 0.47, respectively. High value areas are mainly concentrated in areas densely distributed with woodland, garden, cultivated land and water area, while low value areas are mainly concentrated in the central urban area and its surrounding areas. （2） Nine important ecological source areas are identified, including Taihu Lake, Dongshan Mountain, Xishan Mountain, Qionglong Mountain, Dayang-Tianchi Mountain, Wangshan-Shangfang Mountain, Yangcheng Lake, Changyang Lake and Taipu River. （3） We extracted 36 ecological corridors and 32 ecological nodes, among which, 19, 17, 27 and 5 are important ecological corridors, general ecological corridors, important ecological nodes and general ecological nodes, respectively. The connectivity between Taihu Lake and its surrounding ecological source areas in the southwest of the region is good, and the ecological correlation is high. The connectivity between the northeast of the region and other parts is poor, and the ecological network needs to be improved. It is suggested that the width of important ecological corridors should be 100-200 m, and that of general ecological corridors should be 60-100 m in Suzhou city. （4） The overall ecological network closure is relatively low, the ecological network connection level is complex, the ecological node connectivity is relatively low, and the ecological network cost is relatively high in Suzhou city. Priority should be given to the construction of ecological corridor with great importance, namely, strengthening the construction of ecological corridor among large areas of water and wetland, and improving the connectivity between water area and surrounding mountains and hills. This study is expected to provide useful references for exploring the application value of ecosystem services, implementing the integrated development strategy of Yangtze River Delta, and assisting the construction of ecological civilization.