To prevent the lacquer base layer from peeling off the pottery body of Qin Terra-cotta figures, several strengthening reagents based on modified silicones were used to glue aged lacquer pieces to treated pottery surfaces. Five aspects of the reagents, including velocity of solidification, fluidity, osmosis, ductility and adhesive strength, were evaluated. The adhesive strength of reagent is related to characteristics of the reagent, the solidification temperature and the film area ratio after solidification. Modified silicone reagents can wet both the pottery and the Chinese lacquer pieces. Good bonding effects could be achieved by choosing the right technique. Formula A3, a mixture of silicone, xylene and triethanolamine, performed well and could be used for conservation of painted lacquer layer of Qin Terracotta figures