The present invention relates to the 14-3-3 protein which is a non-alcoholic fatty liver regulating factor. According to the present invention, two isoform proteins of 14-3-3, i.e., 14-3-3β and 14-3-3γ, are different regulating factors for regulating the transcriptional activity of PPARγ2. 14-3-3β increases the transcriptional activity of PPARγ2 by binding to PPARγ2, on the other hand, 14-3-3γ plays a role in decreasing the transcriptional activity of PPARγ2. Thus, 14-3-3β and 14-3-3γ, which are PPARγ2 regulating factors, are proteins that play a vital role in lipid metabolism, and may be used as a target for the prevention or treatment of fatty liver.