The invention discloses a fluorescent isothermal nucleic acid amplification method. The amplification method comprises the following ingredients: a Tris buffer, potassium acetate, magnesium acetate, dithiothreitol, polyethylene glycol, ATP, dNTPs, creatine phosphate, a single-chain binding protein, a recombinant enzyme, a UvsY protein, a DNA polymerase, an exonuclease, a fluorescent probe and a primer group. The method can be applied to carry out real-time fluorescence monitoring on DNA; and based on the method, addition of an RNA retrovirus cane realize RNA amplification. The isothermal nucleic acid amplification method comprises the steps as follows: (1) extracting DNA or RNA; (2) adding the DNA or RNA to a nucleic acid amplification system; and (3) mixing evenly, adding the mixture into a fluorescence detection instrument, reacting at 35-45 DEG C for 5 to 30 minutes to observe a fluorescence signal. The method has the advanategs of simple operation, fast response, low requirements for operators, and broader range of applications.