Using the first-principles self-consistent discrete variational method based on density functional theory, we have investigated the effect of impurity P on the electronic structure of the kink on the ［100］(010) edge dislocations in bcc iron. Furthermore，we have calculated the segregation energy, the interatomic energy, the local density of states and the charge density. Our results show that the P atom proeures electrons from its neighboring Fe atoms when trace P is introduced into interstitial sites in the kink. It is found that the interactions between impurity P atom and neighboring Fe atoms are strengthened due to the strong hybridizations between P-p with Fe-3d4s4p states. The migration of kink and dislocation motion are impeded by P, which may be beneficial to increase the strength of material. Meanwhile, the bonding between the impurity P and the host Fe atoms are mainly ascribed to contribution of p and d states, which leads to the bonding between them to have strong orientation. This is not beneficial to the toughness of materials.