Activated nitrogen-enriched carbon/reduced expanded graphite composites (ANC/REG-c) with different composite ratio were prepared by in-situ polymerization, carbonization, activation and reduction of aniline and expanded graphite. These were characterized by XPS, SEM and electrochemical measurements. XPS shows that N atoms exist in the ANC and ANC/REG-c. Compared to mechanical mixture of ANC and REG(ANC/REG-m), ANC/REG-c shows lower resistance and higher Cp1 (185.4 F/g) vs 124.3 F/g of ANC/REG-m measured by CV due to the introduction of the composite sturcture. When the composite ratio of ANC/REG-c is 6:1, the ANC/REG-c shows the highest Cp1 (264.0 F/g) and its symmetric supercapacitor also shows the best synthetical electrochemical performances. The optimal supercapacitor presents good cycle stability. ANC/REG-c is a suitable electrode material for supercapacitors.