The building of a powerful country in education urgently requires exploration of new evidence regarding the relationship between educational human capital and economic growth. Previous studies on measuring a country’s educational human capital dominantly employed indicators such as the mean years of schooling attained by the population. However, an increasing number of scholars argue that measuring a country’s educational human capital should utilize the mean cognitive skills of students. Nevertheless, means can only depict the location of the distribution but cannot reflect the overall differences in the distribution of cognitive skills among populations of different countries. Additionally, there may be significant differences in the distribution of cognitive skills between students and adults in various countries. This study constructs a database of adult cognitive skills for 73 countries and regions from 2000 to 2020. By using three indicators of skill distribution, i.e. the mean, coefficient of variation, and skewness, to respectively reflect the overall level, disparity, and skewness structure of a country’s educational human capital, we empirically analyze the impact of these three indicators on national economic growth. We find that the skewness structure of human capital distribution has been a major driving force behind economic growth in various countries since 2000. The more left-skewed the distribution of adult cognitive skills in a country, indicating a higher proportion of highly skilled individuals, the faster its average economic growth rate in the long term. Moreover, with economic development, the promoting effect of left-skewness on economic growth continues to increase. Improving the quality of higher education and implementing immigration policies contribute to increasing the proportion of highly skilled individuals, leading to a left-skewness shift in the distribution of adult skills, while expanding the scale of higher education does not have a significant impact. The building of a powerful country in education should follow the basic path of “closing the gap in basic education and enhancing the quality of higher education,” establishing a value-added evaluation system centered on human skill development, adhering to the openness of higher education to the world, lowering the threshold for the influx of international talents, and introducing top-notch international educational resources.