The invention relates to a method and a device for compressing and decompressing a genome. According to the embodiment, the method for compressing genome comprises the following steps: selecting a reference genome matching with the genome from a reference database; building an index based on the position of the sections included in the reference genome; comparing the genome with the reference genome based on the sections, identifying the discrepant data between the reference genome and the genome; generating the compressed genome, and the compressed genome at least comprises the index and the discrepant data. In other embodiments, a device for compressing the genome is provided, the method and the method for decompressing the genome compressed by the method and device is also provided. By adopting the technical scheme, the data compressing rate is improved, and the specific location of the genome can be visited without decompressing the whole genome.