Problems are everywhere in daily life. The ability to solve problems helps human being survive natural selection, characterizing us as an intellectual species. It is also closely related to various life outcomes. A number of cross-sectional studies have demonstrated that intellectually-gifted children performed better than their average cohorts in problem solving tasks. But most of these studies primarily focus on the cognitive dimension of problem solving. They did not suffice to draw a whole picture of human problem solving ability. Moreover, few studies have explored the group differences from a developmental perspective, such as their developmental patterns or developmental critical stage, which could contribute a lot to both theories and educational practices. The present study investigated the developmental differences of problem solving ability between intellectually-gifted and intellectually-average children from cognitive, metacognitive and efficiency dimensions. Both cross-sectional and longitudinal data were collected. The cross-sectional study included 131 intellectually- gifted and 163 intellectually-average children aged from 11 to14, and the longitudinal study included 32 intellectually-gifted and 38 intellectually-average children aging from 11 to 13. A redesigned Sokoban game was used to measure the three dimensions of problem solving ability simultaneously. The number of successful solutions was adopted as indicator of cognitive ability, ratio between planning time and total time as indicator of metacognitive ability, and total moves as indicator of cognitive efficiency. Results showed that the intellectually-gifted were significantly superior to their intellectually-average cohorts in the three dimensions. Moreover, both cross-sectional and longitudinal data showed obvious developmental cascade of the three dimensions. However, the development patterns differed between the two groups. In the intellectually-gifted group, problem solving ability at the age of 13.73 and 12.46 was significantly higher than that at the age of 11.12, but no significant difference was found between the 13.73 and 12.46. In the intellectually-average group, however, problem solving ability at the age of 13.73 was significantly higher than that of 11.12 and 12.46 years old, but no significant difference was found between the latter two. Further, both cross-sectional and longitudinal data revealed remarkably higher score of the intellectually-gifted in earlier years but smaller group difference at the age of 13.5. The major finding of the present study was that problem solving ability of intellectually-gifted and intellectually-average children followed different developmental patterns. The development of the intellectually- gifted accelerated during age of 11~12.5 and slowed down during age of 12.5~14. In contrast, intellectually- average children developed slowly during the age of 11~12.5 and accelerated during age of 12.5~14. Group differences of problem solving ability diminished gradually as they grew older. Different development patterns may be attributed to the synaptic pruning and myelination of neurons. This finding has important implications for educational practice. In order to better cultivate intellectually-gifted children, educational professionals should make full use of their advantages at earlier years and provide enriched educational environment to develop their non-academic abilities, such as sociality, self-regulation skills.