The invention provides an efficient SBP decoder for segmentally increasing an information bit R information initial value. The efficient SBP decoder is composed of an information bit reliability sorting module, an information bit segmentation processing module and a G- Matrix verification module and the like. The invention discloses a method for selecting information bits based on Gaussian approximation, sequencing processing is carried out on the information bit reliability from large to small to obtain an index vector (shown in the specification), and then the index vector (shown in the specification) is subjected to vector alignment (shown in the specification); sequence of the number of subvectors is shown in the specification, the initial value of the information bit R information inthe vector (shown in the specification) is sequentially increased, and finally, re-decoding and utilizing the G-Matrix check to find decoding optimization. The method can be regarded as an informationbit to be converted into a frozen bit to a certain extent, namely, the effect of improving the decoding performance when the code rate is reduced without changing effective information can be achieved. The method is simple and effective, searching, changing and checking are only carried out when decoding is wrong, the error correction capability is greatly improved, the optimization effect of BPdecoding performance is obvious, and the bit error rate performance is improved by 0.25 dB when n is equal to 16.