Abstract: Without any protection treatment, reinforced concrete shall be corroded in harsh environment, and the durability of concrete structure must decrease significantly thereby. The organosilicon impregnating agent is a common method for protecting the reinforced concrete against damage. It consists of alkyl alkoxy silane and/or siloxane. In the UV irradiation conditions, C-C and C-H bonds in the molecular structure will be destroyed due to low bond energy, and thus concrete loses hydrophobicity. In the study, three organosilicon impregnating agents (LS-A(BS1701), LS-B(70% BS1701 and 30% BS290) and LS-C(isooctylsilane cream)) were selected as the test materials to carry out a research on their properties of resistance to 2 600 h UV aging. By tracking the water absorption and surface hydrophobicity process of the organosilicon penetranting specimen mortar, the test results indirectly reflected the anti-aging properties of the organosilicone impregnating agents. In addition, the anti UV aging properties of the organosilicon impregnating agent in concrete pores were studied by surface polishing. The test results show that LS-B has the best resistance to UV aging properties. The water absorption increased slightly and the concrete surface is contact angle after treated with LS-A and LS-C as almost unchanged in the initial 600 h test time. The whole tendency of the contact angle decay and the water absorption increase is almost synchronous. When concrete surface polished after 2 600 h UV aging tests, the surface contact angle has a certain degree of recovery. According to those results, it can be expected that numerous small alkyl groups will be favorable to improving the anti-aging properties of the silicone penetrant; a larger alkyl group is beneficial to the early anti-aging properties; and the UV aging has little influence on the organosilicon impregnating agents in the concrete pores.