Generally speaking, Dabao's performance in a two-child family is better than Bauer's, and this difference is more obvious in the age group of 12- 15. From the social factors, the only child receives better educational resources than Dabao and Bauer. From the perspective of family factors, parents' total educational expenditure and expected results for Dabao are higher than Bauer's, and Dabao's participation in remedial classes is also significantly higher than Bauer's. Of course, our own factors are also very important. Dabao, who has a better academic record, is often the one who has a longer study time. It is true that no pains, no gains.