Objective To analyze the effect of the numbers of transferred good-quality embryos on pregnancy outcomes in in vitro fertilization-embryo transfer(IVF-ET), supplying a reference for selection of transferred embryos.Methods Five hundreds and one infertile patients who underwent IVF-ET were retrospectively analyzed. All cycles were divided into 3 groups by the number of transferred good-quality embryos(group A: two good-quality embryos, group B: one goodquality embryo, group C: no good-quality embryo), with no significant difference in general condition such as age, infertility duration and infertility types. The pregnancy outcomes were compared and analyzed among the three groups.Results 1) Live-birth rate was improved with increasing good-quality transferred embryo numbers. Groups A(70.3%) and B(69.8%) had no significant difference(P=0.409), whereas it was significantly greater in groups A and B than in group C(57.7%)(P=0.009, P=0.036). 2) The loss of single gestational sacs rate, which have no significant difference among 3 groups(P=0.221, P=0.539, P=0.226), reduced with increasing good-quality transferred embryos numbers. 3) Biochemical pregnancy abortion rate in groups A(10.9%) and B(10.1%) was significantly lower than that in group C(18.3%)(P=0.049, P=0.049). 4) There was no significant difference among3 groups in ectopic pregnancy rate(P=0.174, P=0.129, P=0.404). 5) Multiple-birth rate was improved with increasing good-quality transferred embryos numbers, it was significantly greater in group A(31.6%) than in group C(15.0%)(P=0.020), while groups B and A had no significant difference(P=0.489, P=0.126).Conclusion Two good-quality transferred embryos have no significantly difference to 1 good-quality embryo in all pregnancy outcomes. In clinic treatment, we can select1 good-quality embryo and 1 poor-quality embryo when patients only have few good-quality embryos. Meanwhile, a good-quality embryo can improve live-birth rate and multiple pregnancy rate simultaneously. In order to meet a better assisted reproductive technology(ART) outcome, we need to seek a balance between pregnancy rate and multiple pregnancy rate. Objective To analyze the effect of the numbers of transferred good-quality embryos on pregnancy outcomes in in vitro fertilization-embryo transfer (IVF-ET), supplying a reference for selection of transferred embryos. Methods Five hundreds and one infertile patients who underwent IVF- All cycles were divided into 3 groups by the number of transferred good-quality embryos (group A: two good-quality embryos, group B: one goodquality embryo, group C: no good-quality embryos), with no significant difference in general condition such as age, infertility duration and infertility types. The pregnancy test were compared and analyzed among the three groups. Results 1) Live-birth rate was improved with increasing good-quality transferred embryo numbers. Groups A (70.3% ) and B (69.8%) had no significant difference (P = 0.409), it was significantly greater in groups A and B than in group C (57.7%) (P = 0.009, P = 0.036). 2) The loss of single gestational sacs rate, whic 3) Biochemical pregnancy abortion rate in groups A (10.9%) and B (10.1%), with a significant difference among 3 groups (P = 0.221, P = 0.539, P = 0.226) ) was significantly lower than that in group C (18.3%) (P = 0.049, P = 0.049). 4) There was no significant difference among 3 groups in ectopic pregnancy rate (P = 0.174, P = 0.129, P = 0.404). 5) Multiple-birth rate was improved with increasing good-quality transferred embryos numbers, it was significantly greater in group A (31.6%) than in group C (15.0%) (P = 0.020), while groups B and A had no significant We found that both good-quality embryos have no significant difference to 1 good-quality embryo in all pregnancy outcomes. In clinic treatment, we can select 1 good-quality embryo and 1 poor-quality embryo (P = 0.489, P = 0.126) when patients only have few good-quality embryos. Meanwhile, a good-quality embryo can improve live-birth rate and multiple pregnancy rate.ly. In order to meet a better assisted reproductive technology (ART) outcome, we need to seek a balance between pregnancy rate and multiple pregnancy rate.