Activation of PPARα by WY14643 ameliorated hepatic steatosis through increasing lipids oxidation promoting genes CYP4A10, CYP4A14, FGF21, adiponectin, SIRT1 and PGC-1α expression, and suppressing fatty acid synthesis promoting genes FAS and PI3K expression. The gene discussed is FGF21; the disease is Hepatic steatosis.