Abstract: Plate-and-bar aluminum alloy heat exchangers have been widely used because of high reliability. Brazing in Nitrogen atmosphere has high efficiency, good temperature uniformity and low cost. This paper introduced the structure, material and application of plate-and-bar aluminum alloy heat exchangers. This paper also introduced brazing furnace, process, method and parameters which are used in mass production. Brazing is the most important process in manufacture. Brazing failure will result in product failure, and low percent of pass will bring about high cost. So in this paper, the brazing failure modes of plate-and-bar aluminum alloy heat exchangers are defined by four types in manufacture practice: deformation of top plate, parts translocation or deformation, higher or lower brazing temperature, and leakage in brazing gap. The reasons for the four types of failure modes were analyzed. Measures were put forward on brazing fixture design, process management, brazing process and part cleanness, which turned out to be effective.