Abstract: Provided are a method for performing a PCR reaction using a PCR reaction system, a PCR reaction system, as well as a composition, a freeze-dried powder, and a diluent. The PCR reaction method includes: subjecting the piston to the first and second movement processings, to subject the diluent entering the injection chamber, the pyrolysis freeze-dried powder, and the sample to a first mixing processing; subjecting the first mixture to a pyrolysis processing; subjecting the piston to the third and fourth movement processings, to subject the pyrolysis liquid entering the injection chamber and the remaining diluent to a second mixing processing; subjecting the piston to the fifth and sixth movement processings, to allow the second mixture to enter the injection chamber and undergone a third mixing processing with the freeze-dried powder of the reverse transcriptase and the PCR raw materials; and subjecting the third mixture to a PCR amplification processing.