〔Abstract〕 Objective To explore the effects of melatonin(MT) on the fertilization of in vitro matured oocytes in controlled ovarian hyperstimulation(COH) cycles and the development of subsequent embryos. Methods Imma-ture human oocytes from COH cycles were collected for in vitro maturation(IVM) culture and intracytoplasmic sperm injection( ICSI) insemination,and then the cleavage embryo and blastocyst culture medium supplemented with 0,10-11,10-9,10-7or 10-5mol/L MT were used in order to perform embryo culture in vitro,next the formed high-quality blastocysts were picked up and cryopreserved via vitrification,finally,array-CGH technology was used to detect aneuploidy of rewarmed high-quality blastocysts. Results The blastocyst rate of 10-9mol/L group was significantly higher than that of 10-11,10-7,10-5and 0 mol/L groups( P<0. 05,P<0. 01,P<0. 000 1,P<0. 01),respectively; the high-quality blastocyst rate of 10-9mol/L group was higher than that of other groups,but there were only significant differences compared with 10-5mol/L and 0 mol/L groups( P<0. 01,P<0. 05); the incidence of aneuploidy in MT group( 17. 6%) was lower than that in non-MT group( 33. 3%),but no significant difference was found. Conclusion The addition of MT to human embryo culture medium can promote the in vitro development of embryo,which is related to concentration,and 10-9mol/L is the optimal concentration.