The major purpose of this paper is to explore sex differences in science education. Through a theoretical analysis of related research literature on both boys and girls' achievement of science, attitutes to science and science course selection as well as sex bias in science teachers and science curriculum, this paper comes to a conclusion that, indeed, there are sex differences in science education. Male students' are better in achievement of science, attitutes to science than female student; they also outnumber female students in science course selection. In addition, there is a sex bias of science learning for male students in science teachers and science curriculum. Sex differences in science education may be caused by the factors of personal science-related experiences, spatial ability and male images of science and scientist. From this point of view, it is reasonable for us to construct an integrated model with these three factors to interpret the sex differences in science education. For further research, we need to study some rooted factors such as culture, general ability and substance of science, to justify their influence on sex differences in science education.