Offshore fish cage becomes an important marine culture facility because it has a relatively large volume to provide sufficient culture capacity with special designed structure to withstand strongerwave,flow and wind forces at open water areas.This paper gives an overview of classification methodology of cages based on their working mode,structures,material and performances,etc.Their structures,mechanical properties,ability of survival in stronger wave and current have been discussed on the 17 selected types of cages which are currently used in marine aquaculture around the world.The results indicated that,according to their working mode,the varieties of floating type cages are the most with 52.9%; According to the cage structures,the gravity type and self-tensioned-and-self-supporting type cages account for 52.9% and 41.2% respectively;According to the flexibility of frame,the cages can be classified as the flexible frame(or non-rigid frame) and the rigid frame,their proportions are about the same;According to frame material quality,the metal cages are the most widely used up to 52.9%.In those,the gravity cages show good performance and are widely used in fishery due to simple structure,lower costs,easy operation,however,higher tension existing and concentrated on part of the netting or meshes,which might cause netting tearing and the reduction of volume of cage due to stronger current etc.,will bring about limitation on the application of gravity cages in the open water area with strong current.The rigid self-tensioned-and-self-supporting cages have advantages having a stable operation platform and easy to apply modern automatic technology or facilities.It can be expected that the rigid self-tensioned-and-self-supporting cages will be widely applied to cage culture while new material and technology are introduced.