A physiological information detection system includes an image-capturing unit, an image-processing unit and a data-transmitting unit. The image-capturing unit is provided to capture a series of images of head portions and connects with the image-capturing unit to receive the captured images. The image-processing unit is operated to process the captured images and to trace a head portion area and a neck portion area thereof in the processed images. The image-processing unit is further operated to process the captured images to retrieve temperature data from the selected head portion area and the selected neck portion area. The image-processing unit is further operated to convert variations of the temperature data into estimated pulse data. The data-transmitting unit connects with the image-processing unit to transmit the estimated pulse data to a predetermined device.
