聚合酶連鎖反應（polymerase chain reaction, PCR）的技術，包含去氧核糖核酸（Deoxyribonucleic acid, DNA）序列的直接分析、去氧核糖核酸及細胞種類的分析、基因定位突變、基因表現與選殖及食品檢驗等，廣泛應用在醫學、學術等研究領域。聚合酶連鎖反應為利用酵素對特定基因做體外或試管內大量合成的技術，聚合酶連鎖反應進程為一循環反應，每一循環包括變性作用、引子接合作用、延長作用三個步驟，此三個步驟在不同溫度下於同一試管中進行。本篇文獻將回顧聚合酶連鎖反應的原理及操作方法，提供讀者對聚合酶連鎖反應有基礎認識。

The applications of polymerase chain reaction (PCR) technique include the direct analysis of Deoxyribonucleic acid (DNA) sequence and cell types, and detection of gene mutation, expression and clone selection. Its application in early diagnosis of hereditary diseases has been widely used in the field of biological and medical research. PCR is a DNA amplification technique, which in the presence of DNA polymerase and dNTP, allows us to amplify specific DNA sequences in vitro, and results in increased ability to detect the target DNA sequences. The basic method consists of repetitive cycles of three reactions: denaturation, annealing and extension, each carried out at different temperatures. This article will review the principle and operation procedure of PCR, we hope to provide readers a basic understanding of this technique.