Abstract: Good sleep quality during pregnancy plays a very important role in health of mothers and fetus.Around the world, the quality and influencing factors of sleep during each trimester of pregnancy were also studied more specifically and quantitatively.It is an inevitable trend to observe and intervene separately in different trimesters of pregnancy.Based on the results of research on the subjective sleep quality in the second trimester of pregnancy both at home and abroad, this paper mainly studies the influencing factors on the quality of sleep during the second trimester of pregnancy, mainly focusing on the social demographic, psychological and other factors.The second trimester is a key stage to prevent and adjust sleep quality of pregnant women.Dual approaches of education for pregnant women and community support should be explored to enhance their sleep quality, thereby improving the outcome of fetal birth.