Recent reports have suggested the involvement of gut microbiota in the progress of later-stage of colorectal cancer (CRC).Changes in microbiota of precancerous lesion as CRC adenoma in association with CRC development remains undetermined.Here,we characterized the microbiota of adenomas mucosal biopsy specimen together with non-adenomas biopsy specimen and stool samples from 18 clinical subjects by sequencing bacterial 16S rRNA gene with novel library generation strategy.