On the vast Qinghai-Tibet Plateau, the unique natural environment has created a unique traditional food culture in northern Tibet, which has led to the custom of herders living in northern Tibet to like eating milk and dairy products. If we talk about the food of herders, in addition to the characteristic yak meat and barley, the rest are mostly dairy products. On the vast land of 15.66 million mu in Nagqu, the fresh milk squeezed out by tens of thousands of cattle and sheep can be transformed into many different dairy foods and dairy drinks in the hands of herders. After long-term production practice, people have explored a variety of methods for producing various dairy products. Milk residue, "Lala" and so on are the best sources of technology for producing modern dairy products. Many dairy products also have health and diet therapy effects, which have attracted widespread attention from scholars at home and abroad. However, in northern Tibet, according to the traditional dietary customs of herders in northern Tibet, food can be divided into two categories: "Gasai" (vegetarian) and "Masai" (meat). Among the "Gasai", there are well-known butter tea, sweet tea, milk residue, cheese, and yogurt, but there are some foods that many people don't know, such as "Lala" and "Tu". In summer, hardworking herdsmen will make yogurt with fresh milk and freeze it, which becomes yak yogurt ice cream, which people love very much. If we want to talk about dairy products, we have to start with the nomadic culture of herdsmen. The Qinghai-Tibet Plateau, known as the "Roof of the World", its vast land has always been the home of the Tibetan people. Every morning, the first thing women do when they get up is to milk the cattle and sheep. Some women will tie up the front and back legs of the cows when milking to prevent the cows from running around unsafely, and then untie the rope after milking. Usually before milking, herdsmen will let the cows eat first, and then start milking. Holding a bucket of fresh milk that has just been milked, the herdsmen's food journey begins. The first step is filtering. The herders use a very dense gauze to filter the milk from one bucket to another, and the sand, cow hair and other debris are separated from the milk. They often filter it two or three times. Then put the filtered milk on the yak dung stove and stir it evenly with a long spoon. The control of time depends on the herders' experience. After the milk is cooked, it is set aside to cool, and the yogurt (buttermilk) left over from the last time is added, which acts like yeast for making dough. Then the milk with natural yeast is placed in different small basins and covered with thick quilts. After two or three days, it becomes the yogurt that people often eat. The sourer the yogurt, the better. The Tibetan people's diet is inseparable from both raw and cooked yak meat every day. Yogurt not only nourishes qi and blood, but also has beauty effects. It contains lactic acid bacteria. For the Tibetan people who often eat meat, it has obvious therapeutic effects on tuberculosis, indigestion, cardiovascular and other diseases. If you go on a long journey, drinking a few bowls of yogurt is really refreshing. It can not only satisfy hunger, but also quench thirst and prevent heatstroke. Especially when the "Shoton Festival" comes in summer every year, it is the day to eat yogurt. Yogurt has become one of the indispensable foods for Tibetan people when they "go through the Linka". Yogurt is a common dairy product. In northern Tibet, according to the "Gasai", the method of making it is that the herders boil the milk and wait for it to cool down a little, then take the milk skin on it, add a little butter pulp to it as fermentation koji, cover it with a thick quilt to keep it warm and ferment it into cheese. The next day, pour the cheese into a wooden butter barrel, and after whipping it up and down hundreds of times, the oil and butter pulp will be naturally separated, and butter can be extracted from it. After taking the butter out of the barrel and cooling it in cold water, make the butter into round or cone shapes, and wrap it with a sheep's stomach to make "Mazhu". This is the large piece of butter product we can see on the market. After taking out the butter, pour the remaining butter pulp into the pot and cook it. As the temperature increases, the milk residue and juice will naturally separate, and the milk residue will float on top. Then pour the milk residue and juice into the filter container for filtering. The juice flowing out of the filter container is generally used to feed livestock. The filtered milk residue is placed on a blanket made of cow wool to dry, and it becomes the cheese that people are familiar with. In the high-altitude and oxygen-deficient northern Tibetan grasslands, dairy products have extremely high nutritional value and are an indispensable food for herders. Different production processes and techniques can make milky white milk into people's favorite dairy products.