Board spectral photodetectors are required for varied scientific and industrial applications, yet the studies of such devices are limited. In this work a CdSe/ZnS quantum dots (QDs) based photodetector with broad spectral detecting ability was fabricated through a simple approach. Due to the discrete electronic states of QDs, the photodetector was more sensitive to incident wavelengths than incident power densities, and the photocurrent decreased monotonously with increasing incident wavelength, which could also realize the wavelength detection of incident light. This character provides a new way to achieve color or image sensing, and it could also broaden the photodetection and photosensing applications of QDs and semiconductor detectors. (C) 2015 Published by Elsevier B.V.