Objective To organize measurement comparison among provincial CDC gamma spectrometry laboratory for verification of the precision and accuracy of the measuring results from each laboratory and to improve the ability and level for radionuclides measurement in building materials.Methods The method for gamma spectrometry measurement comparison was referred to the method of IAEA international comparison in 2002.Results The results of these labs in this comparison agreed with the reference results well.About 50% labs' relative biases were less than 5%,over 80% labs were less than 10%.Conclusions The results of this comparison showed that the analysis method for the radioactivity content in building materials by gamma spectrometry in each lab was credible and meet the request of the standard GB 6566-2001 "Radioactive Nuclide Limit for Building Materials".