The molecular dynamics (MD) and nudged elastic band (NEB) methods are employed to investigate the dynamic properties of the reconstruction defect (RD) on 908 partial dislocation in Si. This involves the motion of RD in single-period (SP-RD) and double-period (DP-RD) structures. When the temperature is lower than 1100 K, the migration processes and velocities of SP-RD can be simply observed. It is found that SP-RD is remarkably mobile, which is essentially determined by its structural characteristics. At relatively higher temperature, the previous prediction that SP-RD may act as the nucleating center of a double kink is proved. All these MD results are in good agreement with the calculated barriers. The migration of DP-RD is carried out by the motion of left-right kink RD complex (LR-RD) and right-left kink RD complex (RL-RD). Their motion sequences are described in detail and it is also found that the dangling bonds make the movement of the two complexes easier.