An intrinsic relationship between surface area, cortical thickness and folding was found in adult mammalian brains across species, which was thought to relate to the mechanism of cortical folding. However, this relationship remains unclear in the dynamic developing human infant brains. To fill this gap, we jointly analyze surface area, cortical thickness and folding at birth, 1, and 2 years of age, using 219 longitudinal MRI scans from 73 infants. We reveal that the relationship between these cortical properties is gender-independent, but age-specific, with a substantial change in the first year and a subtle change in the second year.