The invention discloses an automobile brake assembly fatigue test stand, which includes a base and a thermotank, wherein a mandrel is mounted inside the thermotank, two ends of the mandrel are respectively inserted into a first taper sleeve and a second taper sleeve, the first taper sleeve is mounted inside a hollow brake tooling, one end of the brake tooling is connected with a first bearing pedestal casing, the other end of the brake tooling is connected with a brake, the first bearing pedestal casing is sequentially connected with a brake shaft, a static torque sensor and a support; the second taper sleeve is mounted inside a brake drum tooling through a bearing, one end of the brake drum tooling is connected with a brake drum sleeved on the mandrel while the other end is connected with a brake drum shaft, and the brake drum shaft is sequentially connected with a second bearing pedestal casing, a coupling, a reducer and a first servo motor. The mandrel is additionally mounted between two tooling fixtures, the tooling fixtures can freely rotate around the mandrel and support the two tooling fixtures, so that the rigidity of the tooling fixtures is enhanced, and the stability during testing is guaranteed.