Based on the previous analysis of the surface coating of ancient Tibetan wall paintings at Labrang Monastery in Gansu, drying oils, such as tung oil and linseed oil, were employed to explore and reconstruct the procedure for making and the process for brushing traditional varnish. Also, a new varnish originating from traditional varnish recipes but combined with the advantages of modern oil-based paint is proposed. This new varnish is accessible and controllable in its structure and composition, and is compatible with the original historical surface coating. The structures of the traditional and “new-traditional” varnishes were analyzed using Fourier transform infrared (FTIR) spectrometry. The color, appearance, aesthetic effects and weatherability of the traditional and “new varnishes” were also evaluated and compared with modern synthetic varnishes, such as alkyd, fluorocarbon and novolac. The results indicate that the traditional and new-traditional varnishes have achieved the same chemical stability and weatherability as synthetic ones, while exhibiting better compatibility and aesthetic effects. These varnishes could be used as surface coating materials for Tibetan wall paintings in the future.