We have synthesized a composite of MoO2@Cu@CusingathermolysistemplateofPOM@MOFcrystal(POM=polyoxometalates, MOF=Metal⿿organic frameworks), in which the Keggin-type Mo-based POMs with negative charges exist as secondary building units of Cu-based MOF. In addition, the material is confirmed to exhibit an excellent capacity of 28.33mAhg⿿1 at a current density of 1Ag⿿1, which is much higher than MoO2-based supercapacitors reported before. Moreover, we have fabricated a symmetrical flexible all-solid-state device with the MoO2@Cu@C electrode using PVA-KOH gel polymer as electrolyte and separator, and it shows outstanding sTable performance retaining 91% of its highest charge capacity maintained after 5000 cycles. The present study displayed a novel thermolysis template in the term of POM@MOF and provided an accessible foundation for investigations of MoO2-based supercapacitors.