We propose that the rotational kinematics of the globular cluster system ( GCS ) in M31 can result from a past major merger event that could have formed its bulge component .
We numerically investigate kinematical properties of globular clusters ( GCs ) in remnants of galaxy mergers between two disks with GCs in both their disk and halo components .
We find that the GCS formed during major merging can show strongly rotational kinematics with the maximum rotational velocities of \sim 140 - 170 km s ^ { -1 } for a certain range of orbital parameters of merging .
We also find that a rotating stellar bar , which can be morphologically identified as a boxy bulge if seen edge-on , can be formed in models for which the GCSs show strongly rotational kinematics .
We thus suggest that the observed rotational kinematics of GCs with different metallicities in M31 can be closely associated with the ancient major merger event .
We discuss whether the formation of the rotating bulge/bar in M31 can be due to the ancient merger .