Biometrics is the one of the security mechanism for computer network security. It is science and technology of measuring and analyzing biological data of human body, extracting details from the acquired data, and comparing the data to the stored in database. Existing system is unimodal biometric system. The proposed system is supported fusion techniques multimodal biometric system. However Multimodal biometrics requires storage of multiple biometric templates for each user, which results in increased risk to user privacy and system security. This paper will discuss the concept off biometrics, biometric working process, unipolar biometrics, bipolar biometrics and multipolar biometrics with their fusion techniques.