We report on current-induced thermal power investigation of graphene nanostructure for potential local-heating applications.It is found that the efficiency of heating can be greatly improved if graphene is patteed into structures with narrow width and long channel.In a narrow graphene-ribbon,the Joule heating power exhibits an obvious dependence on the back-gate voltage.By monitoring Raman spectra,the temperature of graphene-ribbon can be determined.The temperature of graphene-ribbon is modulated by the electric field effect when the sample is sourced with a relatively high current.