Masers have become a promising tool to probe obscured regions at small scales, such as the innermost region of AGNs, due to the extremely bright maser spots. The two main molecular megamaser species found to date are H2O and OH molecules. H2O megamasers are believed to be related to AGN, which become a valuable tool to investigate a series of key astrophysical issues in studying AGN and cosmology, e.g., estimating the mass of super-massive black hole, probing physics and kinematics of accretion disks or tori, determining accurately the black hole-bulge mass relation and providing a perspective to improve the accuracy of the Hubble constant H0. And OH megamasers are found in (U)LIRGs, which are considered to be associated with galaxy merger-induced starbursts. Thus OHMs can trace the galaxy merging activities, which provide potential important tool for providing constraints on merging history of galaxies and further other merging-related projects (e.g., star-forming history, galaxy evolution models). A brief summary and our recent related projects will be introduced, including a systematic observational study of radio properties of H2O megamaser galaxies, FAST OH megamaser survey etc.
