Abstract: The interference correction of 80Brm to 80Br determination in neutron activation analysis are studied theoretically and experimentally. The results indicate that interference contributions of 80Brm to 80Br increase with the increase of the irradiation time and decay time. The contribution factor is about 15%～18% when the decay time is 1 hour and irradiation time are 10 to 300 s. The results of present experiments confirm the reliability of the correction equations based on the decay scheme. The uncertainty after correction can be controlled in less than 2% when the counting statistic is good enough(smaller than 1%).