The Double Ninth Festival, which falls on the ninth day of the ninth lunar month every year, is a traditional Chinese festival. According to the ancient "I Ching" (Book of Changes), "six" is defined as a yin number and "nine" as a yang number. On the ninth day of the ninth lunar month, both the sun and moon are yang, and two nines coincide, hence it is called the Double Ninth Festival or Chongjiu. The ancients considered this day a fortunate and auspicious time, and they have celebrated this festival since ancient times.

The activities to celebrate the Double Ninth Festival are rich and varied, including going out for sightseeing, climbing high mountains, appreciating chrysanthemums, wearing dogwood, eating Double Ninth cakes, and drinking chrysanthemum wine.

The Double Ninth Festival, because of its homophonic relationship with "long lasting", and since "nine" is the largest number in the numerical system, it implies longevity and health. Moreover, autumn is the golden season for harvest, and the Double Ninth Festival has profound significance, with people always having a special feeling towards this festival. There are many excellent poems in Tang and Song dynasty poetry that celebrate the Double Ninth Festival and praise chrysanthemums.

Today, the Double Ninth Festival has been given new meaning. In 1989, China designated September 9th of each year as the Senior Citizens' Day. This cleverly combines tradition with modernity, becoming a festival for respecting, honoring, loving, and helping the elderly. Throughout the country, government agencies, groups, and communities often organize retired elders to go on autumn outings, enjoy scenic spots, or take part in water-related activities or mountain climbing to exercise their bodies, allowing them to be embraced by nature. Many families also have the younger generation accompany the elderly to go out of town or prepare delicious meals for the elderly.