A screen plate, a packaging method, a display panel and a display device are provided. The screen plate includes a frame, a mesh fixed onto the frame and a masking film arranged on the mesh. A printing area is formed in a portion of the mesh that is not masked by the masking film. At least one masking line is arranged in the printing area. The at least one masking line is arranged along an edge of the masking film respectively. A width of the masking line is greater than a width of each mesh line of the mesh.