Previous studies of mating age preference thresholds usually use five ages as one unit and compare the thresholds among units to discuss the age effect and gender effect on the age thresholds. No studies have ever tried to compare the thresholds by each age. The present study statistically analyzes each age preference threshold from 20 to 44 years old by using the individual level data in a mate selection web site in Taiwan. The main findings are: (1) the younger a man is, the higher possibility (on average, before 33 years old) he can accept a mate older than himself. In contrast, the older a woman is, the higher possibility (on average, after 28 years old) she can accept a mate younger than herself. (2) Women between 26 to 34 years old have the strictest age preference (the narrowest gap between ceiling and floor age thresholds). (3) Comparing with an American sample (in a previous study), Taiwanese men have a lower ceiling age threshold. This means that the acceptance of an older mate for Taiwanese men is lower than American men. (4) Between 25 and 33 years old, the spouse's age difference of each age is near the men's ceiling age thresholds. In contrast, it is near the women's floor age thresholds. These results are discussed by using evolutionary theory and marriage market theory in the paper.