This is the second-year report of a three-year longitudinal study on the mental develop ment of Chinese children and adolescents in their school years. The subjects were 688 students sampled from two elementary schools and two junior high schools in Taipei area. Progressive Matrices, Wechsler Intelligence Scale for Children-Revised, Cognitive Abilities Test, and Matching Familiar Figure Test were administered to the subjects. The data obtained were statistically treated by t test, analysis of variance, Scheffé method of multiple comparisons, and Pearson product-moment correlation. The main findings of the study were as follows: 1. The mean scores of the 2nd, 5th, and 8th graders on PM and WISC-R were significantly higher than the mean scores obtained one year before. 2. With regard to the amount of intellectual growth, there were significant differences among elementary school children in lower grade level, upper grade level, and junior high school students. 3. There were significant correlations between intelligence and verbal, mathematical, and global academic achievements of the 5th and 8th graders.