Abstract: The interaction mechanism between screw dislocation and 010 interstitial dislocation loop in BCC-Fe was carried out by molecular dynamics (MD) simulation. It is found that their interaction mechanism is different when screw dislocation slips close to different sizes of dislocation loop at different temperatures. When the size of dislocation loop is 1.5 nm, 010 dislocation loop is stable at 2 K, screw dislocation can slide and pass through it, then react with it to form a 1/211^-1^- dislocation loop, and the critical shear stress increases significantly. With the temperature increasing to 300 K and 600 K, 010 dislocation loop is unstable, and it can transform into a 1/211-1- dislocation loop. The 010 dislocation fragment can be generated by the reaction of the new 1/211^-1^- dislocation loop with screw dislocation, which weakens the hindering effect on screw dislocation slip and decreases the critical shear stress increment. With the temperature further increasing to 823 K, screw dislocation is easy to cross slip and has no contact with the dislocation loop during the whole shear process. Therefore, there is no hindrance. When the size of dislocation loop increases to 4 nm, the stability of 010 dislocation loop increases, and the hindering effect of dislocation loop on screw dislocation slip also increases from 300 K to 823 K.