With the aging of the population, the acceleration of the urbanization process, and the change of life concepts and ways, the mobility of the elderly has become an increasingly popular and new phenomenon in big cities. However, the continuous gathering of the elderly in big cities has also brought great challenges to the social and economic development, elderly care service and public management of big cities. Based on the dynamic monitoring data of Shanghai floating population in 2018, this paper adopts mathematical statistics and spatial analysis method and takes Shanghai as an example to deeply explore the multidimensional characteristics of the elderly floating population in China’s big cities in the new era, which can reveal new problems caused by the agglomeration of floating elderly, and propose countermeasures for the management and regulation of the elderly floating population. It can also provide scientific basis for other big cities and even the whole country to manage the elderly floating population and cope with the issue of aging. The study finds that since 2010, the total size of permanent resident population and the size of floating population in Shanghai have begun to slow down simultaneously, while the number of elderly floating population has shown an upward trend, and the sex ratio of floating elderly is low, most of them are young and non-agricultural, the education level is mainly junior middle school and the male is generally higher than the female, and the education level of non-agricultural elderly is much higher than that of agricultural elderly. According to the new characteristics and problems of the elderly floating population in Shanghai, it is necessary to establish many public management and service optimization strategies for the social support of the elderly floating population in Shanghai under the background of the Yangtze River Delta integration strategy.