Integrating sensors and cloud computing, sensor-cloud is a very powerful system for users to obtain big data in green city. In this article, toward big data in green city, we first review the latest work concerning big data and sensor-cloud, respectively. Further, we introduce three types of sensor-cloud (i.e., PSC, ASC, and SSC) for green city. Specifically, about PSC, participatory sensing is incorporated into sensor-cloud for sensing big data. In terms of ASC, an agent is incorporated into sensor-cloud for transmitting big data. For SSC, a social network is incorporated into sensor- cloud for sharing big data. Finally, the open research issues with respect to big data and sensor- cloud are discussed, respectively. We hope this article can serve as enlightening guidance for future research regarding big data in green city.