Abstract: In order to study the performance difference between refill friction stir spot welding lap joint and resistance spot welding lap joint of aluminum alloy material, refill friction stir spot welding and resistance spot welding tests were carried out with 2024 aluminum alloy material. The micro-structure, micro-hardness and cross peel strength of welded joints obtained by different welding methods were analyzed and compared. The results show that the joint shape of refill friction stir spot welding is better than that of resistance spot welding for the 2024 aluminum alloy. The micro-structure of it is belong to the smaller equiaxed crystal structure and not the columnar crystal structure. So, the mechanical properties of joint are improved significantly, and that shows the technical advantages of refill friction stir spot welding.