Astronomy areas in the elementary science textbooks of Korea and the U.S.A. have been compared to find advantages and disadvantages of Korean textbooks. The analysis objects are the 7th national curriculum science textbooks for Korea and the Macmillan McGraw-Hill(MMH) science textbooks for the U.S.A. The results are as follows: First, in contexts, Korean science textbooks contain mostly inquiry activities and partly reading materials. However, MMH ones contain mostly explanations including photographs, related activities, and various reading materials. Second, in the contents and order, the observation activities of constellations are emphasized in Korean science textbooks, while the MMH ones explain solar system up to the universe in details. In addition, Korean science textbooks deal with one subject only once during the whole elementary course while MMH ones deal with one subject repeatedly in several grades. Third, in the frameworks of the international mathematics and science study (TIMSS) 2007, Korean science textbooks do not introduce some contents presented in TIMSS 2007, whereas MMH textbooks introduce every one of them in time. Fourth, the major subjects such as change of moon phases, constellations, the solar system, and change of seasons are handled independently in Korean science textbooks without strong correlation, while they are systematically done related with the rotation and the revolution of the earth in MMH ones.