A method for evaluating a patent document is described, which includes the steps of introducing a set of one or more patent indices, characterizing different aspects of the patent document; combining said patent indices into a Patent Quality index (the PQ), characterizing value of the patent document; and visualizing the value of the patent document by using a color coding of the patent document according to the value of the PQ index. Conveniently, a correspondence between the value of the Patent Quality index of the patent document and the wavelength of a selected color of a visible part of the light spectrum is provided. A corresponding method and system for visualizing results of evaluation of a patent portfolio are described, wherein the value of the patent portfolio is visually displayed as a color cloud in a system of coordinates having axes corresponding to the patent indices, the value of each patent document (the respective PQ index) being displayed as a color point, which coordinates are equal to the values of their respective patent indices, and the colors of the color points are selected in accordance with the values of their PQ indices.