The ideal-reality gap of perceived traits of the same sex and the opposite sex may have an important impact on young people’s marital attitudes. In light of this, the current study investigated the ideal-reality gap of perceived trait in a sample of 155 subjects (55 males and 100 females) via questionnaires. The multiple regression method was used to explore the prediction effect of the gap indexes on marital attitude. The results showed that, for male and female participants, perceived traits of the same sex were more anti-traditional than that of the opposite sex, and significant differences were observed between perceived ideal traits and perceived realistic traits. In terms of marital attitudes, females had a more negative marital attitude than males. Females also had a larger ideal-reality gap of perceived traits of the opposite sex than males. This gap index significantly predicted females’ marital attitudes. The results of the current study may provide a reference for understanding the changing perception of gender traits and for coping with social problems such as the declining marriage rate.