The present invention provides a dual function protein prepared by linking a biologically active protein and an FGF mutant protein to an Fc region of an immunoglobulin, which has improved pharmacological efficacy, in vivo duration and protein stability. A dual function protein according to the present invention exhibits improved pharmacological efficacy, in vivo duration and protein stability, and a pharmaceutical composition containing the dual function protein as an active ingredient may be effectively used as a therapeutic agent for diabetes, obesity, dyslipidemia, metabolic syndrome, non-alcoholic fatty liver diseases, non-alcoholic steatohepatitis or cardiovascular diseases.