According to the third-generation hub unit of automobile, the assembly line can complete such functions as channel measuring & sorting, steel ball storing, flange plate outer ring assembly, nut tightening, negative clearance testing, grease injection and nut riveting, press fitting of bolt, press fitting of gear ring and sensor and ABS wheel speed sensor detection. Through device combination according to the actual production procedure, this line can complete all assembly procedures of the whole third-generation hub units of automobile. Thus, automatic detection of each procedure is realized. Meanwhile, nonconforming products are prevented from flowing into the next procedure. The operation of mechanism is automatically controlled with PLC according to the procedure. Thus, the influences of human factors on product quality are avoided and the precision control is realized. Meanwhile, the assembly quality is guaranteed.