The last day of the lunar year is the final festival among the four seasons of spring, summer, autumn, and winter. As it usually falls on the thirtieth day of the twelfth lunar month, it is commonly known as "the thirtieth day of the lunar month" in the folk, and this night is called "the Eve of the Lunar New Year." On the Eve, people often stay up all night, which is called "keeping watch for the new year." Su Shi wrote in his poem "Keeping Watch for the New Year": "Children are unwilling to sleep, and they keep each other company in joyful chatter." The Eve of the Lunar New Year is one of the most significant traditional festivals in China. On this day, people thoroughly clean the indoor and outdoor environment, even the corners that are rarely visited, must be cleaned carefully. There is a saying: "Firewood has its own shape, charcoal has its own form, water is sprinkled on the street, and earth is used to fill the latrine. Inside and outside the courtyard, there is a joyous atmosphere." It is also customary to paste door gods, couplets, New Year paintings, and paper decorations on the doors, and people wear new clothes with auspicious colors and patterns.

In some villages of the Lüliang area, adults and children carry water buckets to the river gully to fetch ice blocks. After bringing them back, they are placed in a cool place, and when it is deep into the night, the ice blocks are broken into sizes like fists and scattered throughout the courtyard. Also, four large blocks of ice are placed at the four corners of the courtyard, symbolizing that silver is full of the courtyard and the family is prosperous.

In some small mountain villages in Shanxi, the elderly go to the spring to draw water, which is called "purifying water." Traditionally, wine was used to worship deities and ancestors. However, due to poverty in the mountainous areas, water was used instead of wine. Now that life has become affluent, mountainous areas have begun to use wine for worship, but the elderly still maintain the habit of using both water and wine.

One night connects two years, and three watches separate two years. On the Eve of the Lunar New Year, people rarely sleep. Elderly people cherish time and do not want to spend it in sleep. Young people are energetic and do not sleep either. Housewives will take out everyone's new clothes for a final check and then hand them over to each person for safekeeping, to be worn the next day. A family gathers together, playing or chatting. Most families now have a television set, and they watch programs such as the Spring Festival Gala. This activity of staying awake is traditionally called "staying up for the New Year."

On the Eve of the Lunar New Year, the folk custom is to eat cakes, which symbolize a continuous rise in fortune. They also eat noodles, symbolizing long life. Eating a few dumplings at midnight is called "exchanging the child." When the clock strikes twelve, the most grand Spring Festival begins, and all the celebratory activities of the Spring Festival start.