Education equality is a worldwide problem that has existed for a long time. Women in science, technology, engineering and math (STEM) fields need special attention because they are at a disadvantage in STEM education. In this article, the manifestation of gender discrimination against women in STEM education will be presented and the causes will be discussed. Women who are willing to major in STEM, they cannot get as equal chances as men can in getting access to STEM education. And the exceptions from society and family are different. Besides, for women who are majoring in STEM, it is hard for them to be as competitive as men in academic achievement because of lower self-efficacy caused by gender stereotypes. Based on the two phenomena, the disadvantages of women will be discussed in detail. Women are disadvantaged in STEM education because they cannot get enough returns and a sense of gain, and gender stereotypes also decrease women's interest in enrolling in STEM education.