The present invention relates to two visual detection reagents of isothermal amplification products of nucleic acids, the two visual detection reagents are that 1-(1-hydroxy-2-naphthalene azo)-6-nitro-2-naphthol-4-sodium sulfonate or derivatives thereof (hereinafter referred to as the reagent 1) and 4-(2-pyridine azo) resorcinol sodium salt or derivatives thereof (hereinafter referred to as the reagent 2), the two visual detection reagents are used alone, at the beginning of a reaction, the reagent 1 combines with magnesium ions to become red, and the reagent 2 combines with the magnesium ions to form an orange complex, with the reaction, by-product pyrophosphate groups combines the magnesium ions to form a precipitation, the reagent 1 or loses the magnesium ions to become blue from red, the reagent 2 becomes yellow from orange, amplification reaction results can be judged by color change, detection without opening of a cover can be realized by the method, the aerosol pollution can be overcome, and the false positive problem caused by primer dimmers can be solved.