The field line random walk (FLRW) of magnetic turbulence is one of the important topics in plasma physics and astrophysics. In this article by using the field line tracing method mean square displacements (MSD) of FLRW is calculated in all possible length scales for pure two-dimensional turbulence with damping dynamical model. We demonstrate that in order to describe FLRW with damping dynamical model a new dimensionless quantity $R$ is needed to be introduced. In different length scales dimensionless MSD shows different relationship with the dimensionless quantity $R$. Although temporal effect impacts MSD of FLRW and even changes regimes of FLRW, it dose not affect the relationship between the dimensionless MSD and dimensionless quantity $R$ in all possible length scales