The present invention provides a screen assembly, a screen printing system and a screen printing method, belonging to the field of screen printing technology, by means of which the problem of prior art that the printed pattern has unsmooth lines caused by deformation of a thin film screen after a plurality of times of printing can be solved. The screen assembly of the present invention comprises a thin film screen and a fixed screen both having a same pattern. When a packaging cover plate is printed, the thin film screen is arranged above the fixed screen, and the fixed screen is arranged on the packaging cover plate, so that the printing material passes through the thin film screen and the fixed screen successively to be printed onto the packaging cover plate. The screen assembly of the present invention is particularly applicable to the printing process of glass material.