The context-aware application system is widely used in industrial production and our daily lives.This paper mainly focuses on aspects related to the context-aware application system,such as data collection,secure data transmission & management,and constructs the architecture of the context-aware application system,including the context data acquisition unit,the data transmission network and the cloud data center.The data are collected by sensors,and transmitted to the field supervision unit,then to the cloud data center by the Internet,of which the whole processes are secured through various security protection methods,including sensitive data encryption & isolation,access control,authorization management,audit logs,and backup & recovery.Security of context data is emphasized and practiced in the whole data processes from data collection to data transmission,storage,application,management and so on.