The invention discloses an electrochromic grating, a display panel and a display device. The electrochromic grating comprises a cathode, a first electrochromic layer, an ion transport layer, a second electrochromic layer and an anode which are overlapped, wherein materials of the first electrochromic layer and the second electrochromic layer are opposite in natures in an oxidation state and opposite in natures in a reduction state, namely, the oxidation state of the material of the first electrochromic layer is a dark state, the reduction state of the material of the second electrochromic layer is a dark state; or, when the reduction state of the material of the first electrochromic layer is a dark state, the oxidation state of the material of the second electrochromic layer is a dark state, because when the materials of the first electrochromic layer and the second electrochromic layer are opposite in the oxidation state or reduction state, the first electrochromic layer and the second electrochromic layer can be simultaneously in dark states of two layers, the electrochromic grating realizes ultralow transmittance and further realizes relatively high contrast ratio, thereby improving the display effect.