The present disclosure provides a manufacturing method of a flat panel liquid crystal antenna, including the following steps: providing a first substrate, wherein the two sides of the first substrate are provided with a first metal film layer and a third metal film layer respectively; simultaneously patterning the metal film layer on the two sides to obtain a patterned first metal film layer and a patterned third metal film layer; providing a second substrate, wherein one side of the second substrate is provided with a second metal film layer; patterning the second metal film layer to obtain a patterned second metal film layer; and oppositely bonding the first substrate and the second substrate to form a liquid crystal cell, and preparing a liquid crystal layer. The present disclosure also provides a flat panel liquid crystal antenna by using the above method.