Pit mud is the key to wine making. Liquor brewing with unique style not only has specific natural environmental factors, but also the unique quality characteristics of pit mud are determined by its unrepeatable quality. The ancient pit mud of Qiangshutang wine is carefully cultivated by using the sediment of Mata Lake in Huantai in the late Qing Dynasty and the unique cinnamon soil in Huantai area. Generally, pit mud turns gray after 2 years, black after 5 years, and gray again after 10 years, with red and green flora. Nowadays, the minimum age of Qiangshutang ancient pit mud is 60 years, and the oldest is nearly a hundred years. Pit mud contains a lot of organic matter in local soil, which is beneficial to the growth of brewing microorganisms. These microorganisms play a wonderful role in enhancing fragrance, sweetness and alcohol during fermentation. Qiangshutang's pit is fermented with small stone pits combined with ancient pit mud. Small stone pits are all piled with bluestone, and the pit wall and bottom are covered with a layer of ancient pit mud. These ancient pit mud and stone pit fermentation make the ancient pit mud softer, more delicate, more nutritious, impermeable to water and air, and more bacteria, especially Clostridium. The company cooperated with Institute of Biology of Shandong Institute of Light Industry to analyze and compare the microorganisms in pit mud produced by Qiangshutang. The results showed that there were a large number of caproic acid bacteria and methanogenic bacteria, as well as a small number of butyric acid bacteria and propionic acid bacteria.