A grating light valve′s structure improvement is proposed based on its working principle.The optical characteristics,structure characteristics and fabrication technology of the improved grating light valve are analyzed.In the improved structure,silicon dioxide layer is on silicon substrate as isolation layer and amorphous silicon is deposited on silicon dioxide layer as sacrificial layer.Movable ribbon′s material is silicon nitride and fixed ribbon′s is aluminium film.After ion etching and chemical etching,the structure of bridge-like shape is got.Through study,satisfactory results were obtained including small black area,low driving voltage and high optical intensity,and this kind of grating light valve has potential future in application.