This application discloses a new class of fused tricyclic heterocycles of formula (I), preparation methods thereof, pharmaceutical compositions comprising these compounds, and pharmaceutically acceptable salts, solvates, or prodrugs thereof, and their uses for the treatment of diseases in which modulation of STING is beneficial, for example, cancers, pre-cancerous disorders, and viral infections.本申請案揭示一種新類別的式(I)之稠合三環雜環、其製備方法、包含此等化合物及其醫藥學上可接受之鹽、溶劑合物或前藥之醫藥組合物以及其用於治療其中STING之調節有益的疾病的用途,該等疾病例如癌症、癌前病症及病毒性感染。