Abstract: A device and a method for detecting tumor mutation burden (TMB) based on capture sequencing are disclosed. The device includes: a panel design module configured to uniformly add population single-nucleotide polymorphism (SNP) sites to a genome and screen out gene regions that show the highest consistency with whole exome sequencing (WES); a data acquisition module configured to acquire tissue and plasma samples of a target object and acquire sequencing data of the samples; an alignment module configured to align the sequencing data with a reference genome to acquire mutation data results; a somatic mutation analysis module configured to perform somatic analysis on the mutation data results to obtain somatic mutation results; a filtering module configured to remove unreal mutation sites from the somatic mutation results; and a calculation module configured to calculate the TMB.