Abstract: Because the impulse response of an acoustic echo path may be several hundred milliseconds long, acoustic echo cancellation is a long-stranding problem and has not been solved effectively. In order to solve this problem an acoustic echo canceller is presented and a new algorithm, self-orthogonalizing alternative constrained Partitioned Block Frequency-domain LMS (PBFLMS) algorithm, is put forward in this paper. This algorithm has good convergence ability, small misadjustment, low computation complexity and small delay. In addition, according to the application on the acoustic echo canceller, this algorithm is modified. Finally the whole echo canceller is implemented by using a single TMS320C30 processor in the ATD-C30 simulator and satisfying results are acquired.