Reinforcement of weathered sandstone relics is an important subject in the conservation of cultural relics. In the present study, we studied the materials and the laboratory techniques for the reinforcement of weathered sandstone relics using a kind of fresh sandstone as samples, the composition of which is the same as that of the seriously weathered stone artifacts at Yungang Grottoes. After chemical treatments of accelerated weathering, the sample has a weathering degree equal to the relics. We examined four materials and seven technical laboratory conditions for reinforcement. The penetration depth, color, salt tolerance, resistance to ultraviolet ageing and compressive strength performance of the samples before and after the reinforcement were measured. Our study demonstrates that ethyl silicate and its oligomers as well as hydroxyl siloxane administered using the decompression-dripping process have the greatest impact on reinforcement of the sandstone. The present study provides useful data for the reinforcement of sandstone cultural relics.