Using the extended nonlinear Schrodinger equations including quintic nonlinearity and the split-step Fourier algorithm,the shape evolution of the second-order soliton pair is numerically simulated for different parameters of positive and negative quintic nonlinearity.The results show that the interaction between the second-order solitons with positive quintic nonlinearity is much different from that with negative quintic nonlinearity.The later improve the shape evolution of the second-order soliton pair in the certain degree,but the shape of the former is deteriorated.The numerical results find the periodical yielding smaller solitons between two second-order solitons may be well restrain under appropriate parameter of the negative quintic nonlinearity.