In this paper, one high speed Turbo encoding and decoding scheme is put forward. In order to achieve high-speed decoding, the improvements of algorithms and structure are discussed. In terms of the structure improvements, the parallel sub-block algorithm is adopted. Constituent Encoder is divided to two parts which are processed in parallel and now decoding twice the original speed. In terms of the algorithms improvements, the SF-Max-Log-MAP algorithm is proposed in order to enhance the decoding performance of Radix-4 Max-Log-MAP algorithm. On the other hand, the effective criterion HDA for stopping the iteration process is adopted which is to reduce decoding delay effectively.