Using 2016 fertility survey data from 12 cities in 6 provinces in mainland China，this study empirically investigates how sex preferences impact couple's intentions for a second child. Specifically, we discuss how the agreement on sex preferences between the husband and wife is related to their intentions for a second child and desire for the sex of second birth. The results suggest that about 59% of the couples have same sex preference, in which the preference for having both a son and a daughter (“Er Nv Shuang Quan”) is the dominant type and no preference is the secondary, while the proportion of only son or daughter preference is low. Couples who have the same sex preference are more likely to reach an agreement about having a second child or not, and they also show the same desire for the sex of second child. Husbands and wives with different sex preferences do not show lower second-child intentions. This is because the sex preference of either husband or wife will lead to higher intentions for a second child. Additionally, for couples who have intentions for a second child, the sex preference of husband rather than wife is more likely to be the same with the desire for the sex of second child.