Abstract: A series of uranium standard samples used for active coincidence non-destructive assay were tested by using active well coincidence counter equipment and JSR-12 coincidence counter. The tested uranium standard samples are consists of 24 pieces of 20 g sample, 4 pieces of 40 g sample and 4 pieces of 80 g sample. The results show that the combined relative standard uncertainty is about 2% for 20 g, 40 g samples and less than 2 % for 80 g sample.