This kit is designed for extraction of nucleic acid (DNA/RNA) in human biological fluids such as nasopharyngeal swabs, sputum, broncho lavage fluid and alveolar lavage fluid. This kit provides all necessary reagents for highly pure viral nucleic acid (DNA/RNA) extraction from samples such as human serum, plasma, urine, cell culture supernatant, nasopharyngeal swabs, sputum, ascites and broncho lavage fluid. The extracted pure viral nucleic acid can be directly applied for Reverse Transcription, PCR, RT-qPCR, RT-PCR, Next Generation Sequencing, Northern Blot and other related assays. Based on the technology of purification of silica gel column, samples are lysed in the high concentration guanidine salt lysis solution, so the nucleic acid could be absorbed on filter membrane by the interaction of hydrogen bond and electrostatic, while proteins and other impurities cannot be absorbed. This kit enables a simple, fast, safe and efficient operation process to extract viral nucleic acid with a high yield, high purity, stable and reliable quality.