In cultural relic restoration, especially in the repair of defective parts of ancient silk paintings and calligraphy, it is almost impossible to prepare homologous silk for repair. Normally, new silk has to be used instead for repair; however, since new silk differs greatly from the original one in strength, color and fiber thickness, it may easily cause further damage to the original rather than achieve a desired effect of repairing it. Considering this problem, this article introduces Japan’s artificially deteriorated silk and its application, based on the idea and principle of “repairing the old as the old” and my experience in repairing ancient paintings during study in Japan. This work aims to provide a reference and some new thoughts for protection and restoration of ancient Chinese paintings and calligraphy.