A physiological detection device including a light source, an image sensor and a processor is provided. The light source illuminates a skin surface using a burst mode. The image sensor receives ejected light from skin tissues under the skin surface at a sampling frequency to successively generate image frames. The processor controls the light source and the image sensor, and calculates a physiological characteristic according to the image frames captured when the light source is illuminating light. The physiological detection device reduces the total power consumption by adopting the burst mode.