Abstract: Oyster tastes delicious and is rich in nutrients such as zinc, taurine and glycogen. With rapid growth, high yield, short food chain and good economic benefits, oyster has become an important shellfish for aquaculture in China and even the world.The main cultivated oyster varieties in China are Crassostrea gigas (also known as Pacific oyster), Fujian oyster (also known as Portuguese oyster), C. ngulata, C. hongkongensis, C. riakensis, C. sikamea, etc.At present, the phenomenon of smaller individuals, slow growth rate, longer growth cycle and decreased quality in the cultivation practice is in urgent need of strengthening the selection and breeding of oyster varieties, and the development of polyploid breeding technology can effectively promote the development of oyster industry to the direction of high quality and high quantity.The main methods of oyster triploid induction include biological hybridization between diploid and tetraploid, physical induction methods such as temperature shock, hydrostatic pressure, electroshock and osmotic pressure, and chemical induction methods such as CB, 6-DMAP and caffeine.This review is expected to provide reference for the study of polyploidy in oysters and other shellfish.