A new method for rapid detecting beer-spoilage by PCR was developed.This method is based on the sequence of a hop-resistance gene horA,which a pair of specific primers were designed based on the partial sequence of it.Using the primers,beer-spoilage Lactobacillus species were detected by PCR.The sensitivity was reached to 3CFU.The pre-enrichment of samples was needed only 12~16 h.The duration for beer-spoilage determination by PCR(24h)was markly shorter than by conventional method(5~7d).