This heat exchanger adopts a double tube sheet structure design, so that the tube side and shell side are connected by their own tube sheets, which minimizes the risk of cross contamination, facilitates timely detection of leakage hazards, and ensures safe production. Due to its small size and high heat exchange efficiency, it is widely used in pharmaceutical, chemical, electronic, beverage, semiconductor and other industries, especially in those occasions where there is insufficient space on site, which further highlights the excellent performance of the product. The ultra-small size and super heat exchange performance can not only provide users with efficient heat exchange, but also reduce installation space for users, and reduce installation and maintenance costs.