Pregnancy is not only a natural biological process, but also a complex and changeable period of emotion. Pregnant women are often influenced directly by life events during pregnancy. They usually face many big physiological and psychological changes which may affect their psychosomatic health and increase the risk of pregnancy complications. Moreover, pregnant women will experience enormous pressure. Therefore, the present study aimed at investigating the relationship between life events and pregnancy stress of pregnant women by adding mediator and moderated mediator, which mental health status was considered as a mediator and husband support as a moderated mediator. A total of 403 pregnant women during their 24~33 weeks pregnancy were administrated to fill out basic information scale, life events questionnaire, pregnancy stress scale and the 10-item Kessler Psychological Distress Scale according to their actual situation. The results showed that: (1) the main effect of gestational age was not significant (F（6,774）=.88, p>.05) whereas the main effect of pregnant plans was significant (F（3,387）=3.07, p<.05). Moreover, gestational age combined with pregnant plans to affect pregnant women’s pregnancy pressure remarkably (F（6,774）=2.47, p<.05), especially in terms of pregnant women who was under 25-year-old; (2) life event was positively related to pregnancy stress and negatively related to mental health of pregnant women (r=.332 and -.252, p<.01); (3) the effect of life events on pregnancy was partially mediated by mental health status of pregnant women, that is, life events exercised an influence on pregnancy stress through mental health status. The proportion of the mediating effect was 11.92 percent. Moreover, husband support moderated the mediating effect which was caused by mental health status (β=-.117, p<.05); when the degree of husband support which was reported by pregnant women was high, mental health status significantly predicted pregnancy stress, that is to say, the mental health status was better, then the pregnancy stress was lower (β=-.479, p<.001); when the degree of husband support which was reported by pregnant women was low, the prediction of mental health status was not significant to pregnancy stress (β=-.071, p>.05). All in all, adjusting mental health status of pregnant women and providing them relevant social support were important to pregnant women, fetus, even families. Husbands, as expectant fathers, should pay attention to wives’ thoughts and feelings, care about their physical changes initiatively, encourage them to face with life events bravely and try to build favorable family atmosphere. All these will be good for pregnant women to have joyful and relaxed emotional experience. Accordingly, pregnant women can reduce pregnancy stress and confidently wait for the coming of a new life. The results also can let some child health care organization and gynecologists attach great importance to give suggestions and provide knowledge and any other beneficial help.