Based　on　Minimum-Mean-Square-Error　(MMSE)　criterion,　a　kind　of　LMS　algorithm　with　variable　step　size　is　proposed　to　suppress　Multi-Access　Interference　(MAI)　in　asynchronous　DS-CDMA　system.　Compared　with　similar　variable　step　size　LMS　algorithm,　computer　simulation　results　show　that　the　kind　of　detector　is　insensitive　to　the　near-far　effect　and　its　structure　is　very　simple.　At　the　same　time,　it　has　lower　bit　error　rate　and　faster　speed　of　convergence　and　tracking　without　increasing　computational　complexity.　In　particular,　the　controlling　parameters　of　proposed　algorithm　are　not　required　to　re-adjust,　even　if　the　channel　parameter　changes.　So　it　can　be　widely　used.