A detection method of nucleic acid is provided. The method includes: providing nucleic acid to be tested, making the nucleic acid to be tested react under asymmetric PCR conditions with a pair of primers for target nucleic acid amplification, DNA polymerase, adenine deoxyribonucleotide, guanine deoxyribonucleotide, cytosine deoxyribonucleotide and thymidine deoxyribonucleotide in a PCR buffer solution, mixing the reaction product and liquid that contains probe molecules, and judging whether the nucleic acid to be tested contains the target nucleic acid by observing the obtained mixture color or color change. A kit is also provided that can be used in the nucleic acid detection by the said method. Application of the method and the kit in inspection and quarantine is also provided. The method is a quick and easy, sensitive and a specific detection method of nucleic acid with direct observation using naked eyes. The method does not need additional equipment.