The invention relates to the technical field of flight vehicles, in particular to a power 
system structure of a coaxial dual-rotor-wing unmanned aerial vehicle. The power 
system structure of the coaxial dual-rotor-wing unmanned aerial vehicle is used for solving the problems of low efficiency and poor stability of an existing coaxial dual-rotor-wing unmanned aerial vehicle power 
system. The powersystem structure of the coaxial dual-rotor-wing unmanned aerial vehicle comprises a miniature 
turboshaft engine, a main stage speed 
reducer and a two-stage speed 
reducer, wherein an output shaft of the main stage speed 
reducer is connected with an input shaft of the two-stage speed reducer, and the main stage speed reducer comprises a 
fuel oil lubricating system; the two-stage speed reducer comprises an input shaft, an inner output shaft 
assembly and an outer output shaft 
assembly, and the rotation direction of the inner output shaft 
assembly is opposite to the rotation direction of the outeroutput shaft assembly; and the two-stage speed reducer further comprises a lubricating oil lubricating system. By adopting the miniature 
turboshaft engine, the main stage speed reducer and the two-stage speed reducer, efficient output of power is realized, and the structural 
layout is simplified. The main stage speed reducer adopts the 
fuel oil lubricating system, the two-stage speed reducer adopts the lubricating oil lubricating system, cooling of the speed reducers is effectively realized, and stable work of the speed reducers is achieved.