A sequencing data analysis method, a device and a computer-readable medium for microsatellite instability. The present invention can use NGS sequencing results to determine whether the microsatellite instability is present. The sequencing data analysis method can significantly improve detection sensitivity without reducing specificity, and can quickly and automatically evaluate a stable or unstable status of each MSI locus with high throughput, high sensitivity, and high specificity. By combining the statuses for all MSI loci in each sample, the samples can be comprehensively evaluated as MSS, MSI-L, or MSI-H.