The present invention provides a method for manufacturing liquid crystal display device, which includes (1) providing a substrate and (2) forming a black matrix on a surface of the substrate and at the same time forming support structures, wherein the support structures are arranged to correspond to the site where an enclosing frame is to be set. The method for manufacturing liquid crystal display device of the present invention forms, simultaneously with a process of forming black matrix, support structures to support box thickness so that the conventional process of adding fibers in sealant to support the box thickness used in the known techniques is replaced. The manufacture process is simplified, while labor deployment is reduced and manufacture cost is lowered down.