In the year of 2006, the European Union used progressive leg-islation to establish the 2006/24/EC Directive, using Retention of In-ternet Data and Communication Data to fulfill the need to prevent se-rious crimes. But this approach has caused debate over whether the Directive has breached the Charter of Fundamental Rights of the EU Art. 7 and Art. 8. Also, Taiwan’s “The Communication Security and Surveillance Act” has been amended in early 2014, explicitly regulat-ing the criteria to access communication records and communica-tions user’s information when State Agency investigate and collect evidence. Whether these respective regulations of EU and Taiwan may lead to the same result, is worth further research. This research will firstly analyze the categorization of possible fundamental rights related to preventive retention communication data. Then, by exam-ining the Judgments of the Federal Constitutional Court of Germany and the Court of Justice of the EU, the application of EU Directive of 2006/24/EC will be observed. This study will also ana-lyze Taiwan’s current and similar regulations and ponder possible constitutional obstacles that could be encountered. At last, personal opinion will be provided, in hope to provide some observa-tion and advice on the path to find the balance point of personal data protection.