In this paper, a low-complexity and full-mode BCH decoder with long block length for DVB-S2 application is presented. With the reversed error locator polynomial, our proposed reversed Berlekamp-Massey algorithm features a sharing architecture to perform parallel-4 syndrome and Chien search calculations. Concatenated with the LDPC decoder, which has a long decoding latency and a short period of data output time, the proposed parallel-4 BCH decoder ensures the sufficient throughput with only one bank memory. Moreover, a composite field divider instead of a large Galois field inversion table is also presented to reduce complexity. After implemented in 0.13μ m CMOS technology, our parallel-4 BCH decoder occupied 44K gate count can reach 380Mb/s according to the post-layout simulations.