Abstract: The problem of consciousness is a difficult problem faced by philosophy and science.Although there are many neuroscientific theories of consciousness,how to understand consciousness is still the most central work in philosophy of mind.In the 1950s and 1960s,physicalists believed that the processes of consciousness were the same as those of the brain.Faced with multiple realizedobjection,physicalists turned to supervenience framework: the mental depend on physical but not reduce to the physical.But this characterization still has a glaring flaw: it fails to capture the intuition that physical things are ontologically more fundamental than mental things.Concepts such as grounding,which have emerged in the field of metaphysics since the 2000,characterize the physicalist intuition that physical is more fundamental than psychology,and expressing physicalism in terms of grounding has thus become a more reasonable position.This paper focuses on the explanatory gap and introduces three approaches: metaphysical ,neuroscientific,and ordinary explanation.By comparing the three approaches,the value and limitations of the grounding concept are clarified,and a new possibility is provided for re-understanding and even bridging the explanatory gap.