The purpose of this paper was to compare the verbal ability of Chinese and Japanese children. A test of Chinese vocabulary in which some items were translated from Shiba's (1978) Japanese vocabulary test was administered to about 3000 Chinese children. An ability scale for Chinese vocabulary was constructed based upon Item Response Theory. Using the set of common items, the ability and item parameters were compared between both Chinese and Japanese children. Then the obtained estimates were studied using two different methods. The results showed that the distribution of abilities in both Chinese and Japanese children was not markedly different.