This study was to explore infant temperament at age of one-month, two-month, and three month, then, to analyze the difference between the results and the norm of EIQT in the U.S. Also, the stability and the consistency of infant temperament were examined. There were 153 neonates participated in this study. Their parents longitudinally rated their infant temperament. The results of this study were as follows: The infants in Taiwan showed high activity and low threshold. The development of regularity, quality of mood, persistence, and distractibility is from low to high. There was the compensative relation between adaptability and approach. There were cultural differences in temperament between infants of Taiwan and United States of America. The stability of temperament from one-month-olds to three-month-olds was found. The continuity of infant temperament was just found in activity level, regularity and intensity of reaction.