The purpose of this study was to revise "Cornell Critical Thinking Test, Level X (CCT-X)" used for evaluating, teaching and selecting elementary and junior high school students in Taiwan. "The Revised Cornell Critical Thinking Test, Level X (RCCT -X)", composed of 49 items, can be completed in 40 minutes. A group of 1511 students, selec-ted from 15 schools around Taiwan, aged from 10-14, was sampled. Analysis of reliability indicated that the revised test had reasonably high internal consist-ency(.67 & .68) and stability (.66 & .71). The concurrent validity of this revised test was gained by using the criterion of Ross higher order thinking test. The result of constructive validity test of the RCCT-X based on 3 categories, gen-der, IQ and grade, supported the hypotheses, further inferring the agreeable val-idity of the revised test. Percentile rank norms were developed for the total population and for categories.