The kit is based on rapid nucleic acid amplification technology at room temperature and constant temperature, its principle is that at room and constant temperature, the recombinase and primer form a protein/single-stranded nucleotide complex Rec/ssDNA, and invade the double-stranded DNA template with the help of auxiliary proteins and single-stranded binding protein SSB; then form a D-loop region at the invasion point and start to scan the DNA duplex, after finding the target region complementary to the primer and disintegration of the complex Rec/ssDNA, the polymerase also binds to the 3' end of the primer to start the chain extension. The kit relies on the role of exonuclease and adds the designed specific molecular probes according to the template at 39℃, and achieves the real-time monitoring of amplification process of the target fragment.