We investigate the influence of Kerr medium on the concurrence of the two-atom system under the condition of existence of dipole-dipole interaction. The entanglement of the system is calculated by making use of concurrence. We discuss the variation of the concurrence with time. The result shows that the appropriate choice for the nonlinear coupling constant χ of Kerr medium can improve the concurrence of the system and restrain effectively the intrinsic decoherence of the system. We also find that with respect to increasing concurrence, the multiple Λ may take different values as Ω varyies.