Repeat Accumulate(RA) codes have attracted great research interests because of their low coding and decoding complexity and good performance close to the Shannon limit. This paper introduces RA codes and their decoding algorithms, and then proposes the RA Bit-Interleaved Coded Modulation(RA-BICM) scheme. An improved scheme with iterative process between demodulator and decoder has been brought forward to reduce the bit error ratio of the system, especially in the low SNR environment. Simulation results show that the iterative scheme bears distinct performance improving both AWGN and Rayleigh fading channels compared with the former system.