An emotion-sensing system comprises a data processing device. The data processing device comprises a communication module, a processing module, an analysis module, a calculation module and an emotional status generation module. The communication module is used for receiving a plurality of photoplethysmographic signals of the user. The processing module is used for processing the plurality of photoplethysmographic signals to obtain a plurality of pulse-to-pulse interval data. The analysis module is used for analyzing the plurality of pulse-to-pulse interval data to obtain different power values and different power average values. The calculation module is used for calculating a pressure level and an emotion value based on the different power values or/and the different power average values respectively. The emotional status generation module is used for comparing the emotion value and the pressure level with the demographic data to deteil line the emotional status of the user.
