I read the manual of LAMMPS and found QEQ module seems to have not the CHARMM fluctuating charge model. If I want to use CHARMM fluctuating charge model,should I modify the code to satisfy this requirement? I think qeq/dynamic seems to do it.
No, but the DRUDE package does.
Also by the way using Drude oscillators will maintain fixed charges on your atomic species, but they will account for fluctuating dipole moments. Not sure for which specific kinds of problems using something like QEQ is more appropriate.