〔Abstract〕 Objective To investigate whether there is correlation between the occurrence time of key events in fertilized eggs and the formation of high-quality cleavage embryos. Methods Patients receiving in vitro fertilization (IVF) assisted treatment in Foshan Maternal and Child Health Hospital from February 2021 to September 2021 were selected as the research objects. According to the formation of good embryos, there were 724 cases in the group without good embryos and 476 cases in the group with good embryos. To compare the difference of critical event occurrence time between the two groups and its correlation with the formation of embryos. Results There were no significant differences in the synchrony formation time of male and female prokaryotes (tPNa), the contact time of male and female prokaryotes (tPC), the time interval between the synchrony formation time of male and female diprokaryotes and the contact time of diprokaryotes (T1), and the time interval between the disappearance of synchrony between male and female diprokaryotes and the first cleavage of fertilized eggs (T2) between the two groups (P > 0.05). The time of pronucleus fading (tPNf) of male and female prokaryotes in the optimal embryo group was shorter than that in the non-optimal embryo group, and the difference was statistically significant (P < 0.05). However, correlation analysis showed that tPNa, tPC, tPNf, T1 and T2 were not correlated with the formation of embryos. Conclusion There was no correlation between the time of critical events in fertilized eggs and the formation of high-quality embryos.