Abstract: The Vietnam Offshore Current is an offshore eastward jet originated from the Vietnam coast between 11°N and 12°N. It is also known as Summertime Eastward Jet (SEJ) mainly between 110°E to 113°E. The SEJ is a significant component of the South China Sea circulation, with cyclonic circulation in the north and anticyclonic circulation in the south, forming the dipole structure of the South China Sea summer circulation. The adjustment by the basin-scale wind stress curl through first baroclinic Rossby wave dominates the SEJ formation and related circulation. In the source area, the SEJ core has a meridional span of 330 km, can reach depths of 100 m, and has a volumetric transport of 4.6 Sv. The SEJ is gradually decaying and diverging eastward, and significantly decaying to the east of 113°E. In the eighties and nineties of last century, the SEJ was identified successively from observational data and numerical simulations. Since then, with the accumulation of observational data and the development of numerical products, in-depth research on the SEJ meridional migration has been paid much attention to. The SEJ migrates southward or northward when summer monsoon strengthens or weakens. Based on the classic Sverdrup Theory, it can be explained from two aspects in terms of the wind stress curl. One is the north-south migration of the zero-value line of the wind stress curl, and the other is the north-south difference in the change of the wind stress curl in the South China Sea. Recent studies have shown that the joint effect of monsoon intensity and upper ocean thickness can also lead to the SEJ meridional migration. This has improved the dynamic mechanism of the SEJ meridional migration and deepened the understanding of the dynamic process of the South China Sea circulation. Due to its involvement in significant upwelling and the transport of cold water rich in nutrients, the SEJ impact on the local climate and ecological environment deserves our continuous attention and in-depth discussion.