The Na2Ti3O7·2H2O nanobelts (Na-TNBs) with layered structure have been prepared by simple hydrothermal method. The carbon modified Na-TNBs (C/Na-TNBs) supercapacitor has been encapsulated by the flexible and stretching PDMS (poly-dimethylsiloxane), which has flexible and stretching property. The capacitance of the device can attain 459.71Fg−1 at scan rate of 25mV/S and energy density of 33.2Whkg−1 at power density 478Wkg−1 and power density of 2.13kWkg−1 at energy density 25.36Whkg−1. The retention of specific capacitance remains 74.3% after 6000 cycles at high current value of 35mA. Three supercapacitors in series can light 100 green color commercial light emitting diodes (LEDs) for about 10min. All these results indicate that the C/Na-TNBs nanomaterial could provide the potential application in high performance supercapacitor.