The invention relates to an expansion spring type automatic aluminum alloy fixing device which comprises a rivet bolt fixing base, a rivet bolt and a baffle block, wherein one end of the rivet bolt is fixed on the rivet bolt fixing base; a clamping body is arranged at the other end of the rivet bolt; a slot is formed in the rivet bolt along an axial direction; the end face of the slot is of crossing shape; the baffle block sleeves the rivet bolt; a clearance is formed between the baffle block and the rivet bolt fixing base. According to the expansion spring type automatic aluminum alloy fixing device, the stability is improved, looseness cannot occur easily and the overheating and carbonizing phenomena of connecting clamp can be prevented effectively, so that the circuit outage condition can be avoided, the running reliability of transmission line can be improved and the equipment safety can be ensured.