Shanghai people have the custom of eating Qingtuan around Qingming Festival, which can be traced back to the Zhou Dynasty more than 2,000 years ago. According to the "Zhou Li", there was a law at that time that "wooden bells were used to follow the fire ban in the country in mid-spring", so the people stopped cooking and "cold food for three days". During the Cold Food Festival, one or two days before Qingming Festival, it was also designated as the "Cold Day Festival". The traditional foods of the ancient Cold Food Festival included glutinous rice cheese, wheat cheese, and almond cheese. These foods can be prepared in advance to satisfy hunger during the Cold Day Festival, and there is no need to light a fire for cooking. Among the traditional foods of the Cold Day Festival, there is also a kind of "Qingjing Rice". According to the "Miscellaneous Records", "When the Shu entered the Cold Food Festival, they picked Yangtong leaves and dyed rice with fine holly, which was green and shiny." The "Qi Xiu Lei Gao" of the Ming Dynasty also said: "The ancients picked Yangtong leaves on the Cold Food Festival and dyed rice green for sacrifice to provide yang energy. Now it has changed to blue and white dumplings, which means the same thing." The Qing Dynasty's "Qing Jia Lu" has a clearer explanation of Qingtuan: "Qingtuan cooked lotus root is sold in the market, which is a product for worshiping ancestors and can be eaten cold." Nowadays, some Qingtuan are made of green wormwood, and some are made of brome grass juice and glutinous rice flour and then filled with red bean paste. After more than a hundred years, it still has the same old face. People use it to sweep tombs and worship their ancestors, but more people try new things. The function of Qingtuan as a sacrifice is becoming less and less. Therefore, some shops selling Qingtuan have insight into this point. In the past few years, there have been many kinds of Qingtuan with sweet and salty fillings, such as lard rose Qingtuan, black crisp Qingtuan, golden needle ear fresh meat Qingtuan, etc., but the good times did not last long. These Qingtuan, which were originally popular, ended without a disease, which is really puzzling. In the Jiangnan area, there is a custom of eating Qingtuan and Zongzi during the Qingming Festival. Qingtuan, also known as Qingming fruit, is made by pounding bromegrass juice and glutinous rice together to blend the juice and rice flour, then wrapping it with bean paste, jujube paste and other fillings, using reed leaves as the bottom, and putting it in a steamer. The steamed Qingtuan is bright green in color and fragrant, and is the most distinctive seasonal food for the Qingming Festival in the local area. Some families in Shanghai also like to eat peach blossom porridge during the Qingming Festival, and like to use knife fish at tomb sweeping and family banquets.