Objective：To compare the in vitro fertilization（IVF） outcomes between fresh embryo transfer cycles and frozen all-thawed embryo transfer cycles and to evaluate the benefits of the “freeze-all” embryo strategy. Methods：A total of 7 043 embryo-transfer cycles performed from January 2016 to December 2016 in women aged less than 37 years were enrolled. Patients were divided into two groups：3 353 fresh embryo-transfer cycles and 3 690 frozen all-thawed embryo transfer cycles. The demographic characteristics，biochemical /clinical pregnancy abortion rate，clinical pregnancy rate，ovarian hyperstimulation syndrome（OHSS） rate were compared between the two groups. Results：Although the patients receiving frozen all-thawed embryo transfer cycles had a significantly younger age than those having fresh embryo transfer cycles[（30.66±4.16） vs. （31.78±4.39） years，P<0.05]，no significant difference was found in the clinical pregnancy rate（55.77% vs. 55.41%，P=0.760） between the two groups. The incidence of severe ovarian hyper－stimulation syndrome was significantly higher in patients with fresh embryo transfer（P<0.05），but the biochemical pregnancy abortion rat was significantly lower compared with the frozen all-thawed embryo transfer cycles. Conclusion：The fresh embryo-transfer cycle has the similar pregnancy outcome with those of frozen all-thawed embryo transfer cycle. Our results support that only the patients who can’t receive fresh embryo transfer are suitable for the “freeze-all” embryo strategy.