The purpose of this study is to investigate the effects of the storybook instruction to children's learning of number conservation. Before the experiment started, researchers adopted the「Test of Early Mathematics Ability- Second Edition,TEMA-Ⅱ」to test twenty-six 4-5 year-old preschoolers’ understanding of number conservation. Eighteen children pretested as not mastering the number conservation concept participated in this study, half assigned to the training group with the instruction of number conservation using storybooks and the other half, control group with regular counting instruction. The same TEMA-II test items were administered to these preschoolers after the experiment. Results showed that the instruction of number conservation using storybooks effectively accelerated children’s understanding of number conservation.