The connection of atomic clusters has been investigated using molecular-dynamics simulation to explain the splitting of the second peak of the pair-distribution function in amorphous alloys. It is found that the unevenness of the connecting style of atomic clusters results in the splitting of the second peak and the two subpeaks are caused by a three-atom-shared connection and a one-atom-shared connection between atomic clusters. The underlying reason is that metallic glasses have higher density than liquid alloys and a different connecting style of atomic clusters from crystals.