a blind rate detection method in an asynchronous mobile communication system comprises : restoring data when a path selection value at a last bit &# 39 ; s possible position satisfies a ps condition ; determining whether a ser satisfies a ser condition when no error occurs in a crc ; determining whether to update a minimum value of ps values when the ser satisfies the ser condition ; setting a ps value of the last bit &# 39 ; s possible position as the minimum value of the ps values and the last bit &# 39 ; s possible position as a last detection position when updating the minimum value ; and repeating the above steps until the last bit &# 39 ; s possible position reaches a maximum value , and outputting the last detection position when the last bit &# 39 ; s possible position becomes the maximum value .