Abstract: We developed a low complexity echo canceller suitable for double talk cases on DSP TMS320DM642. It uses the two echo path model (TEPM) as the basic structure to enhance robustness under double talk, and the multi-delay block frequency domain adaptive filter (MDF) as the echo path impulse response estimator to lower computational complexity. For implementation, the echo canceller takes the advantages of parallel processing power and single instruction multiple data (SIMD) capability of the DSP through linear assembly level optimization for main operations. It is shown that the echo canceller is able to process echoes with path delay up to 128 ms at 4.5% CPU load for composite source signals and real source signals.