The invention discloses a structure design method of a combined type knuckle roller bearing. The structure design method is characterized in that a knuckle bearing and three rows of roller bearings which are arranged in the different directions can form the combined type knuckle roller bearing through structure improvement. The combined type knuckle roller bearing comprises a first outer ring (1), a second outer ring (2), a first middle ring (3), an inner ring (4), a second middle ring (5), a combined type seal ring (6), a sealing ring (7), an internal spline (8), a locating pin (9), an outer seal ring (10), a docking bolt (11), a first row roller assembly (12), a second row roller assembly (13), a third row roller assembly (14), a docking seal ring (15) and a middle seal ring (16), wherein the first outer ring and the second outer ring are utilized as knuckle outer rings, the first middle ring and the second middle ring are utilized as both knuckle inner rings and roller outer rings, the second row roller assembly bears the radial force, the first row roller assembly and the third row roller assembly can bear the radial force, and a coaxiality requirement of the inner ring on an assembling shaft in installation is not high.