This paper provides the results of the MD simulations of the interaction between a screw dislocation and a copper precipitate in iron. From the results, the screw dislocation has an attractive interaction with the copper precipitate. Also, the dependence of the Critical Resolved Shear Stress (CRSS) for the screw dislocation to break away from the copper precipitate on the size of the precipitate and temperature is studied. Finally, the CRSS obtained by the MD simulations is modeled statistically using a Russel-Brown model. Then we found that an addition of the Peierls stress, which is calculated by the MD simulations, to the Russel-Brown model gives a good prediction of the CRSS.