The Bell state nondemolition detector technology was proposed via the weak cross-Kerr nonlinearities in the process of quantum teleportation,quantum channel authentication scheme in symmetrical quantum cryptography via weak nonlinearity was presented.After two-bit joint gates were evolved via the weak cross-Kerr nonlinearities medium by two legitimate partners,covering Bell-state that correlated with quantum channel,quantum channel authentication was completed through quantum nondemolition detector(QND)technology.Furthermore,the security performance of the scheme was analyzed in theory.The result showned that the proposed scheme is more efficient authentication to realize the complete performance of quantum channel.