Abstract: In view of problem of echo interference in voice communication of rescue communication system, a self-adaptive echo canceller was designed based on self-adaptive filter using normalized least mean square and voice detection module. Working principle and design scheme of the self-adaptive echo canceller were introduced. The test results show that the self-adaptive echo canceller has rapid convergence speed, which can converge to below -30 dB within 1 s, and basically eliminate audio signal echo.