This investigation aims to observe the intelligence and psychomotor development of the schoolchildren in iodine deficiency (ID) areas after the adoption of Universal Salt Iodization (USI), and evaluate the effect of the adoption of USI on their intelligence and psychomotor development. 564 schoolchildren (306 males and 258 females, age range from 8 to 13 yrs) from areas with severe, moderate, and mild ID were investigated. Intelligence quotient (IQ) was measured by Combined Raven's test, second edition. Psychomotor development was examined by Jinyi Psychomotor Test Battery (JPB). We found that the IQ scores of all subjects in the severe and moderate ID areas were 102 +/- 15.6 and 99.5 +/-16.6 respectively, lower than those in the mild ID areas (108 +/- 12.4, p < 0.01). The IQ scores correlated negatively with age (partial r = -0.17; beta = -1.95; p < 0.0001). The total T scores of JPB of all subjects in the severe and moderate ID areas were 316 +/- 42.3 and 330 +/- 47.7 respectively, lower than those in the mild ID areas (342 +/- 48.1, p < 0.05). The total T scores of JPB correlated negatively with age (partial r = -0.15; beta = -4.94; p = 0.0006). We may conclude that after the adoption of USI in the ID areas investigated, USI has probably made a contribution to the partial recovery of intelligence and psychomotor development injured by ID in schoolchildren, and should be strengthened.