In the series of AVS coding standard, logarithmic domain based adaptive binary arithmetic coder (LBAC) is used with a high data-compression ratio and a hardware-efficient structure. However, the existing software implementation of LBAC is of high complexity, especially for the decoder. Based on the analysis of the mapping mechanism between the logarithmic domain and the original domain, this paper proposes an original domain based acceleration algorithm for LBAC (ODB-LBAC). This algorithm simplifies the existing decoding process of LBAC and is friendly for software implementation. Experimental results show that, ODB-LBAC achieves a speedup of 5.65% and 18.28% in a fully optimized AVS2 decoder, for random-access and all-intra configurations, respectively. At present, this algorithm has been adopted into the AVS3 reference software as the reference implementation of LBAC.