Abstract: To produce tripoids , fertilized eggs of Chlamys(Azumapecten)farreri were treated with 6 -dimethylaminopurine (6 -DMAP)to inhibit the extrusion of the second polar body .Using dihydrochloride (DAPI ) stain and fluorescence microscopic observation , the relation between chromosome karyotype and triploid induction and larval survival percentage , the effects of egg maturation and spawning temperature on the synchronous development of fertilized eggs were analyzed . It was concluded that the optimism induction parameters for farming industry are as following : completely mature eggs , initial treatment time when the first polar body occupied 40 %, 60mg L of drug concentration , 15 min of treatment duration and water temperature kept at 20 ℃ from spawning to the end of treatment .Under the conditions , triploids can be obtained with an induction rate higher than 80 % and an hatching rate up to 70 %.