The invention discloses a nucleic acid extraction kit and a nucleic acid extraction method, and belongs to the field of molecular biology. The nucleic acid extraction kit comprises a lysis solution, awashing solution I and a washing solution II, and the lysis solution comprises Tris, EDTA, Tween20, dithiothreitol and guanidinium isothiocyanate. The nucleic acid extraction method comprises the following steps: mixing the lysis solution, a nucleic acid attachment and a sample to be extracted to obtain the nucleic acid attachment adsorbed with the nucleic acid, cleaning the nucleic acid attachment adsorbed with the nucleic acid by using the cleaning solution I, the cleaning solution II and an eluent in sequence, carrying out solid-liquid separation after each cleaningprocess, and collectingthe supernatant to obtain the nucleic acid. According to the nucleic acid extraction kit and the nucleic acid extraction method provided by the invention, cells can be fully and effectively cracked, the cracking efficiency is high, nucleic acid with higher concentration and higher purity is obtained, the accuracy of subsequent operation is ensured, operation such as centrifugation is not needed, the operation is simple, one-time extraction is carried out within 1 hour, and the extraction efficiency is improved.