Objective To investigate the effect of microRNA⁃155⁃5p（miR⁃155⁃5p）on the pathogenesis of preeclampsia through targeted inhibition of silent information regulator 1（Sirt1）in patients with preeclampsia. Methods From January 2018 to December 2018，placental samples（n = 25）from patients with preeclampsia and normal pregnant women were selected from the obstetrics department of our hospital. RT⁃qPCR was used to detect miR⁃155⁃5p and Sirt1 expression in the placenta. In addition，over⁃expression of miR⁃155⁃5p and knock⁃ down of Sirt1 was performed to determine its effect on HTR⁃8/SVeno cells migration and invasion. Results The expression of miR⁃155⁃5p in the placenta of the preeclampsia group was higher than that of the control group（P < 0.01），and the expression levels of Sirt1 mRNA and protein were lower in the patients with preeclampsia than in the control group（P < 0.01）. There was a negative correlation between miR⁃155⁃5p expression and Sirt1 protein expression in preeclampsia patients（r = -0.636 6，P = 0.016 9）. Over⁃expression of miR⁃155⁃5p and knockdown of Sirt1 in HTR ⁃8/SVeno cells，respectively，inhibited invasion and migration of trophoblast cells（P < 0.01）. Conclusion miR⁃155⁃5p may regulate the migration and invasion of trophoblast cells by inhibiting Sirt1 expres⁃ sion，thus affecting the occurrence of preeclampsia.