Abstract: The effect of self-shield of ~(125)I seed source, container and form of container as well geometry seat of seed on the apparent activity of ~(125)I seed are investigated. The results show that seed sources are carried out under the given a quite severe condition, when the apparent activity measurement of low energy ~(125)I. So, there are several proposals for user to measure the apparent activity of ~(125)I seed source:the source must be put the center of the source disk and measured one by one, while ~(125)I are measured.