There is provided a dip coating apparatus that includes a sealed case assembly for containing at least one workpiece to be coated. The dip coating apparatus also includes an air pump communicated with the sealed case assembly, for pumping air from the sealed case assembly and injecting air into the sealed case assembly. Further, the dip coating apparatus includes a fresh coating solution container containing a coating solution, which is communicated with the sealed case assembly, for injecting the coating solution to the sealed case assembly and a recycle coating solution container, which is communicated with the sealed case assembly, for retrieving the coating solution from the sealed case assembly.