Individual or family charitable donation is not only a virtue

but can also promote harmony between different classes and social stability. The analysis of charitable donation has also become an important tool to understand the public's judgment and action strategies on social inequality. Existing researches on the direction of impact of income inequality on the relationship between family income and charitable donation is still controversial. The analysis of the data from China Labor Force Dynamic Survey (CLDS) in 2012 and 2016 shows that in 2012

the charitable donation of Chinese citizens was mainly influenced by absolute family income rather than relative family income. And by 2016

the relative income formed by income comparison has become the decisive factor for family charitable donation. When absolute income is decisive

the influence of family income on charitable donation increases with the increase of income inequality. When relative income is decisive

the regulating effect of income inequality is the opposite. The research results provide a theoretical explanation for existing controversies

and further reveal the limit of simply improving the absolute income of individuals to promote charitable donation and it is of great significance for public opinions to guide the public to make reasonable social comparisons to guide individuals to actively participate in charitable causes.