The invention relates to a single 
nanowire electrochemical device and an 
assembly and in-situ characterization method thereof. The method comprises the following steps of: dispersing 
nanowire anodes of 
vanadium oxide nanowires, and the like, nano film cathodes of HOPG (
Highly Oriented Pyrolytic Graphite), and the like or 
nanowire cathodes of 
silicon nanowires, and the like and nano film anodes of LiCoO2, and the like on a substrate; respectively making 
metal electrodes at both ends of the nanowires and the nano films as current collectors by adopting technologies, such as PECVD (
Plasma-Enhanced 
Chemical Vapor Deposition), and the like; then, depositing 
silicon nitride or 
spinning a 
photoresist on the 
metal current collectors as protection 
layers of the current collectors by adopting the PECVD technology, and the like; and finally, dispensing a 
polymer electrolyte on the surface of the substrate to finish the 
assembly of the single nanowire electrochemical device. In the invention, charging and discharging tests are carried out on the electrochemical device, then in-situ 
electrical transport performance tests, micro-domain Raman 
spectrum analysis, and the like are carried out on the single nanowire electrodes in different charging and discharging states, the direct relation among the 
electrical transport, the structure and the electrochemical performance of the nanowire 
electrode material is established, a platform is provided for battery diagnosis, and the like and a support power supply can be provided for the 
nano device.