Nickel-cobalt layered double hydroxide (NiCo-LDH) has attracted much attention because of its excellent electrochemical properties and regulability. And it is a potential pseudocapacitive electrode material, which is commonly used in supercapacitors and lithium-ion batteries. Its application in the field of supercapacitors can improve the energy density, power density and cycle life of devices. However, NiCo-LDH still faces some challenges, such as poor electrical conductivity and the capacity attenuation caused by agglomeration of layered structures, which require further research and optimization. In this paper, SnO2 films were prepared on carbon cloth (CC) by magnetron sputtering method, and Ni-Co LDH nanosheets were grown by hydrothermal reaction to obtain NiCo-LDH@SnO2 composites. Due to the synergistic effect between NiCo-LDH and SnO2, NiCo-LDH@SnO2 composites exhibit high Cs and good cyclic stability. In addition, an all-solid-state flexible asymmetric supercapacitor (ASC) was assembled with activated carbon (AC) anodes, showing good specific capacitance(Cs) and energy density. And a high initial capacitance can still be retained after 10,000 cycles. This paper shows that NiCo-LDH@SnO2 shows excellent application potential in supercapacitors.