Abstract: Based on the two-measurement position segmented gamma scanning, the efficiency calculation method of the circular radioactivity source was deduced. According to the source position, its detection efficiency could be calculated in time by this method. A new detection system was built on this basis, which could automatically detect the waste drums. This system was used to measure the simulated waste drums, which was composed of single and multiple ⁶⁰Co and ¹³⁷Cs in polyurethane and wood. The average relative errors of single source and multiple sources are 10% and 7.9%, respectively. The result was better than that measured by the traditional segmented gamma scanning. At last the minimum detection limit of the system was estimated according to the measurement environment.