A manufacturing method for a display panel that includes the following steps: a first substrate manufacturing step, a second substrate manufacturing step, an assembling step, and a first alignment film layer manufacturing step. The display panel includes a first substrate, a second substrate, a liquid crystal layer, and a sealant layer. The manufacturing method for the display panel disposes a first liquid crystal alignment monomer layer on a surface of a common electrode layer, and uses a heat gun to perform heat and light treatment to a color filter substrate to make a link reaction occur between the first liquid crystal alignment monomer layer and the common electrode layer and form a first alignment film layer, and thereby undesirable alignment is improved and greyscale difference of a display panel caused by undesirable alignment is avoided to ensure yields and quality of products.