Sensor-cloud is a combination of wireless sensor networks (WSNs) and cloud computing. The emergence of sensor-cloud greatly enhances the computing power and storage capacity of traditional WSNs via exploiting the advantages of cloud computing in resource utilization. However, there are still many problems that need to be solved in sensor-cloud, such as the limitations of WSNs in terms of communication and energy, the high latency and privacy security issues due to applying cloud platform as the data processing and control center. The core of edge computing is to migrate some or all of the computing tasks of the original cloud computing center to the vicinity of the data source, which gives edge computing great potential in solving the shortcomings of sensor-cloud. After a lot of research, the latest research status of sensor-cloud was analyzed, the characteristics of existing sensor-cloud were summarized, the problems of existing sensor-cloud solution were revealed and the implementation scheme of sensor-cloud based on edge computing was proposed. Finally, the challenges and future research directions of the research in sensor-cloud were discussed.