The traditional technique about making gold foil is a kind of important traditional metal technique in China. The forging is the mostly and only method for making gold foil. It continues to be use from Shang dynasty to the present. At the early times, gold foils were only forged piece by piece because of not to use interlayer. And its thickness could not be very thin. Along with using interlayer material, the thickness of gold foil was reduced very much, especially making use of a kind of special black paper. This kind of black paper appeared in Ming dynasty at least. Until to Qing dynasty, the thickness of gold foils was very thin just like it could fly in the sky. One time one piece of gold foil forged formerly, but now at a twice or two thousand piece of gold foil could be forged together along with the technique development. The manufacture efficiency is increased very much now. In this paper, the traditional technique about making gold foil was investigated in the Nanjin Gold String and Gold Foil Factory. It includes the alloy composition, smelting, working procedure and tools. The pure gold was not used in the process because it is too soft and does not have enough intensity to get paper-thin gold foil. So a certain proportion metal just like silver or copper is added into the pure gold to make it to become alloy. There are several kinds of different shape hammers and beakirons to be used in the different procedure while forging gold foil. There are several kinds of interlayer materials, for example black paper, brown paper and Maotai paper. And there are other kind tools. A board with cat skin on surface and bamboo knife is cutting tools. A plume is a moving tool. The procedure of forging gold foil is as follows. Hammering a gold block to thinner, cutting it into small square piece, putting it in the black paper, bundling twenty or thirty thousands blocks with interlayer of black paper (10cm x 10cm), hammering this package, moving gold foils from small black paper (10cm x 10cm) to large black paper (20cm x 20cm), bundling them, hammering again, and then a very thin gold foil can be got.