Provided are a single cell classification method, a gene screening method and a device for implementing the method. In that, the single cell classification method includes the following steps: sequencing the whole genomes of a plurality of single cell samples from the same group, respectively, so as to obtain reads from each single cell sample; aligning the reads from each single cell sample to the sequence of a reference genome, respectively, and performing data filtering on said reads; on the basis of the filtered reads, determining a consistent genotype of each single cell sample, in which consistent genotypes of all the single cell samples constitute an SNP dataset of said group; aimed at said each single cell, on the basis of the SNP dataset of said group, determining a corresponding genotype for each cell at a site corresponding to a position in an SNP dataset of the reference genome; and selecting an SNP site associated with cell mutation, and on the basis of the genotype of said single cell at the site, classifying said single cell.