Smart building can gather information from the environment inside and outside to optimize temperature, lighting, and other elements. Because of this, Smart building can provide comprehensive, convenient, intelligent, and interactive services for both individuals and their surroundings. While Smart building bringing numerous benefits, it also causes severe threats to user privacy. The data that collected by Smart building, such as sensory data or contextual data, part of them could be seen as personal information. If someone want to design buildings or systems that collect and track any data with personal information, they must be compliant with regulation. Not all company could bear the burden of regulation. For reducing the burden of regulation, this article research smart building data legal issue, and focus on security monitoring question. First of all, this article will interview related operator to understand actual situation, then analyze the practicing law of European, United Kingdom and Japan. At last, this article will according the above research, and propose strategy of security monitoring data application.