A system for integrating heart rate measurement and identity recognition is provided. The system includes a storage unit, an image sensor, an identity recognition unit and a frequency extractor. The storage unit stores a user information database. The image sensor captures a plurality of skin images of a user during a time period. The identity recognition unit receives a physiological feature from the user and recognizes the user by comparing the physiological feature with the user information database in the storage unit. The frequency extractor obtains a frequency signal by extracting a motion signal from the skin images according to the brightness change of the different color lights in the skin images during a time period. The frequency signal represents a frequency in a specific frequency interval, and it represents heart rate information of the user. A method for use in the above-mentioned system is also disclosed.