With the growing popularity of handheld devices nowadays, face recognition becomes the hottest technology after fingerprint authentication in response to the rising trading mechanism of mobile payment and mobile commerce to strengthen personal data protection. Face recognition technology is used to detect and to recognize user’s facial features which can unlock handheld devices and PCs and authorize on-line transactions while convenience and safety are guaranteed for users. The application of face recognition will gradually be introduced to mobile devices to replace the traditional password entry and to reinforce transaction security.