Abstract: The brain-imaging studies on the general fluid intelligence will contribute to the comprehension of the brain mechanism of intelligence. We introduced related researches from two ways: structural imaging and functional imaging. Works on brain structure revealed a moderately positive correlation between general fluid intelligence and the total brain volume and the gray volumes of frontal or other brain areas. The high-g loading tasks induced more active brain activities than the low-g loading tasks in certain brain areas. Early studies revealed a negative correlation between the levels of general fluid intelligence and the levels of brain activation, but later studies had found contrary outcomes. Studies in the future should increase researches of individual differences, combine techniques of brain-imaging with EEG or ERP, clarify the brain mechanism of intelligence by integrating multi-level outcomes

Key words: general fluid intelligence, brain-imaging, MRI, fMRI, PET