Abstract: In the face of declining urban waterfront space vitality, how to awaken the vitality of urban waterfront space and reshape harmonious interactions between man and water has become an important issue in improving the quality of urban space in the process of urbanization transformation. Due to the characteristics of high sample size, fine spatial-temporal granularity and intuitive positioning tracking, the mobile signaling big data provides a new perspective for the study of urban waterfront spatial vitality. Taking Jinji Lake in Suzhou as an example, this research analyzes the temporal and spatial characteristics of crowd vitality in the waterfront space with the spatial-temporal dynamic distribution information of population obtained from the mobile phone signaling big data. It further adopts the Pearson correlation coefficient to study the correlation between the spatial impact factors, such as land use nature, traffic facilities richness, shoreline accessibility, and service facilities quantity with waterfront spatial vitality. It has been found that the most important factor affecting spatial vitality is the number of service facilities. Meanwhile, the richness of transportation facilities also promotes the improvement in spatial vitality. Therefore, it proposes that in waterfront space planning and design, we should focus on the “catalyst” role of public service facilities to stimulate the vitality of waterfront space and encourage compound development of the waterfront space.