A lock set transmission mechanism includes a lock case, a lock core, a transmission rod, a supporting member and a fixing member. The lock core is arranged on the lock case and configured to be driven by a key to rotate relative to the lock case. The transmission rod has a first end configured to be connected to a latch, and a second end. The supporting member includes a first supporting ring sleeved on the lock core, a second supporting ring configured to support the second end of the transmission rod, and at least one supporting rib connected to the first and second supporting rings. The fixing member is configured to fix the supporting member to the lock core. Wherein, when the lock core is rotated relative to the lock case, the transmission rod is driven by the lock core to rotate, in order to move the latch.