The invention relates to the technical field of furniture, and discloses a method for applying a foldable wall desk. The method includes steps of forming a groove in a wall by means of digging, inserting a fixing bolt, mounting the foldable wall desk on the wall and reserving an extending end on the fixing bolt; connecting a fixing plate with a groove onto the fixing bolt in an anchored manner and inserting the extending end of the fixing bolt into the groove of the fixing plate; propping up a desk plate hinged onto the fixing plate and laying down a support rod and legs; supporting adjusting devices on a floor and inserting the support rod into spaces among adjusting teeth in an inclination manner; adjusting the adjusting devices to lift or lower the legs and enabling the desk plate to be parallel to the ground. The extending end of the fixing bolt extends out of the groove of the wall. The size of the groove of the fixing plate is identical to that of the groove of the wall. The support rod and the legs are hinged onto the bottom surface of the desk plate. The adjusting devices are connected to the lower ends of the legs. According to the scheme, the method has the advantages that the inclination of the desk plate can be adjusted, accordingly, the desk plate can be prevented from inclining due to uneven grounds or deformation of components of the wall desk after the components are used for a long time, and the mounting flexibility and the durability of the desk can be greatly improved.