Silicone sealant was prepared using α,ω-dihydroxyl polydimethylsiloxane, dimethyl silicone oil, nano-calcium carbonate, methyltrimethoxysilane, silane coupling agent, and catalyst as raw materials. The effects of four silane coupling agents, namely γ-aminopropyl triethoxysilane (KH550), γ-(2,3-epoxypropoxy)propyl trimethoxysilane (KH560), N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane (KH792), and γ-mercaptopropyl trimethoxysilane (KH590), on the surface dry time, mechanical properties, and adhesion performance to substrates such as PP, PE, and PET of the silicone sealant were investigated. The results showed that the addition of KH550 and KH792 could shorten the surface dry time of the sealant and accelerate the curing speed within 24 hours, but the improvement in mechanical properties was limited, and the adhesion effect to substrates was poor. The addition of KH560 and KH590 could effectively enhance the adhesion effect to substrates, but the mechanical properties of the sealant with KH590 were slightly inferior to those with KH560. The silicone sealant with KH560 exhibited the best comprehensive performance.