Abstract: Biometric authentication (BA) has become an important means of identity authentication. However, many BA systems deployed at present do not take enough consideration in protecting the security and privacy of users biometric data, which has become a main obstacle to the popularization and application of the BA technology. BA systems may face various attacks from software or hardware implementations, among which, template attack is the main consideration. Many technical literatures have been devoted to dealing with this type of attacks. However, existing review literatures suffer from incomplete descriptions or conflicting discussions. In order to systematically summarize the attacking and protection technologies against biometric templates, some related concepts of the BA system is introduced at first, as well as the architecture of a BA system and the connotation of BA security and privacy. Then, template protection technologies for a BA system are classified into two main categories for description: the transformation-based methods and the crypto-based methods, which solves some conflictions in existing literatures. Afterwards, some classical methods and emerging technologies in each category are expounded and analyzed, as well as some subsequent evaluations and improvements. Finally, several major difficulties and the corresponding possible solutions for building a secure BA system are pointed out.