In order to study the evolution of separate spatial soliton pairs in a biased series centrosymmetric two-photon photorefractive crystal circuit,separate spatial soliton screening pairs solitons were proved to stay in a series circuit of two-photon photorefractive crystals based on the centrosymmetric two-photon photorefractive effect.The spatial envelope,dynamical evolution and stability of separate dark-dark and bright-dark soliton pairs were investigated numerically.The results show that only the dark sol...