Isolation of DNA fragment adjacent to a known sequence is a tedious task in genomerelated research.Thermal asymmetric interlaced PCR(TAILPCR) is an efficient technique for isolation of target DNA segments flanking known sequences.It was utilized three nested sequencespecific primers with a shorter arbitrary degenerated(AD) primer respectively.Specific products can be amplified through continuous cycles of amplification at different annealing temperature.The amplified products are suitable for either hybridization probes or sequencing templates.TAILPCR technique is very simple and highly efficient.The specific products can be obtained again in the same PCR mixture and the same PCR condition.All the TAILPCR reaction need only a few time as in one day.It has become a powerful tool in a genomic analysis.This article presents the principle and protocol of TAILPCR.Methods for primers design and products selection are also discussed.