Pregnancy and childbirth are special and important stages in a woman’s life, and due to the great changes in physiology and external conditions, pregnant women may develop negative emotions, which may lead to mental health problems. The study is designed to explore the characteristics of maternal mental health, design relevant experiments, and mine its key factors using principal component analysis. After descriptive statistics and different analyses of the basic information and mental health of pregnant women, the influencing factors of maternal mental health were explored in depth so as to propose mental health care measures for pregnant women. The normative level was not met by the subjects when it came to their SCL-90 scores for maternal mental health factors. The maternal mood is not good and can lead to psychological problems. There were significant differences in maternal mental health across three dimensions: literacy level, work status, and family economic situation. Among the six principal components with a cumulative variance contribution rate greater than 90%, Components 1~6 were the principal component of own feelings, the principal component of basic objective status, the principal component of culture and education, the principal component of economic status, the principal component of social pressure, and the principal component of career development aspects, respectively.