Abstract: In the technical field of molecular diagnosis, a detection primer for detecting tumor microsatellite instability (MSI), use thereof, a kit and method for amplifying tumor microsatellite loci is disclosed. The detection primer includes one or more of microsatellite locus amplification primers selected from sequences shown as SEQ ID NOs: 1 to 26 and can simultaneously amplify a plurality of microsatellite loci in the same PCR system and perform multiplex fluorescent PCR to detect MSI, with no cross peak or overlapped peak among fluorescence peaks generated by electrophoresis of amplified products of microsatellite sites and with high detection efficiency and excellent sensitivity.