Abstract: For the Weighted bit inversion (WBF) of low-density parity check (LDPC) code, a fast combined weighted bit inversion decoding algorithm is proposed. The algorithm firstly USES the average amplitude as the calibration equation, then the decoding error rate is determined by the reliability ratio, and the output result is obtained when the maximum number of iterations or zero error rates is reached. Compared with WBF decoding algorithm, the decoding speed of LDPC code is accelerated, and the error performance is improved obviously. Compared with average amplitude of information node weighted bits flip (AMWBF) algorithm and the Reliability ratio weighted bits flip (RRWBF) algorithm, the improved algorithm avoids the single bit flip algorithm in the process of decoding the same bit cyclic inversion.