Prof. Tao An is the vice director of RadioAstronomy Technique Laboratory in ShanghaiAstronomical Observatory (SHAO), ChineseAcademy of Sciences. He obtained his Ph.D. inSHAO in 2004, then worked there until now. Hismain research interests include active galacticnuclei, transients, and radio astronomy technique.His recent works focus on the high-resolutionstudies of high-redshift quasars and gamma-raybursts. He is now the Chinese delegate of SKAregional central committee and leads the buildingof the prototype of SKA regional center.Development of time-domain astronomy has been accelerated in recentyears, owing to the advance of wide-field optical and radio surveys, aswell as applications of new observing techniques that have led to thediscoveries of gravitational waves and neutrinos of extragalactic origin.The properties and the nature of many of the new classes of transientsources remain unclear, which are found to be associated with peculiarsupernovae, mergers of compact (NS-NS) objects, or tidal disruptionevents. Another interesting class of short-term transients uniquelyobserved in radio band is Fast Radio Bursts (FRBs), discovered onlyten years ago. Nowadays, the detection is boosted by a factor of 10with the SKA pathfinders (e.g., ASKAP, CHIME), enablingbreakthrough in FRB study. However, the physical origin of FRBremains obscure. One of the mysteries in the transient study is theaccurate localization and their physical association with counterparts atother bands. Very long baseline interferometry (VLBI) offers thehighest angular resolution among the current astronomicalobservational techniques, thus plays a vital role in exploring thephysical nature of transients and tracing their structural evolution. Iwill report an overview df the recent high-resolution observations oftransients using VLBI. All these prompt to broaden the understandingof fundamental physics.