  LHAASO J0621$+$3755 is a TeV gamma-ray halo newly identified by LHAASO-KM2A.
It is likely to be generated by electrons trapped in a slow-diffusion zone
around PSR J0622$+$3749 through inverse Compton scattering. When the gamma-ray
spectrum of LHAASO-KM2A is fitted, the GeV fluxes derived by the commonly used
one-zone normal diffusion model for electron propagation are significantly
higher than the upper limits (ULs) of Fermi-LAT. In this work, we respectively
adopt the one-zone superdiffusion and two-zone normal diffusion models to solve
this conflict. For the superdiffusion scenario, we find that a model with
superdiffusion index $\alpha\lesssim1.2$ can meet the constraints of Fermi-LAT
observation. For the two-zone diffusion scenario, the size of the
slow-diffusion zone is required to be smaller than $\sim50$ pc, which is
consistent with theoretical expectations. Future precise measurements of the
Geminga halo may further distinguish between these two scenarios for the
electron propagation in pulsar halos.
