Abstract： Objective To evaluate the efficiency of the application of array comparative genomic hybridization (array-CGH) in preimplantation genetic diagnosis or screening (PGD/PGS), and compare the clinical outcomes of different stage embryo biopsy. Methods The outcomes of 381 PGD/PGS cycles referred in the First Affiliated Hospital of Nanjing Medical University from July 2011 to August 2015 were retrospectively analyzed. There were 320 PGD cycles with 156 cleavage-stage-biopsy cycles and 164 trophectoderm-biopsy cycles, 61 PGS cycles with 23 cleavage-stage-biopsy cycles and 38 trophectoderm-biopsy cycles.Chromosomal analysis was performed by array-CGH technology combined with whole genome amplification.Single embryo transfer was performed in all transfer cycles.Live birth rate was calculated as the main clinical outcomes. Results The embryo diagnosis rate of PGD/PGS by array-CGH were 96.9%-99.1%. In PGD biopsy cycles, the live birth rate per embryo transfer cycle and live birth rate per embryo biopsy cycle were 50.0%(58/116) and 37.2%(58/156) in cleavage-stage-biopsy group, 67.5%(85/126) and 51.8%(85/164) in trophectoderm-biopsy group (both P<0.01). In PGS biopsy cycles, the live birth rate per embryo transfer cycle and live birth rate per embryo biopsy cycle were the same as 34.8%(8/23) in cleavage-stage-biopsy group, the same as 42.1%(16/38) in trophectoderm-biopsy group (both P>0.05). Conclusions High diagnosis rate and idea live birth rate are achieved in PGD/PGS cycles based on array-CGH technology.The live birth rate of trophectoderm-biopsy group is significantly higher than that of cleavage-stage-biopsy group in PGD cycles;the efficiency of trophectoderm-biopsy is better.