The invention discloses a method for designing a detonation return prevention structure of a circular passage based on a complete CCW theory. The method comprises the following steps: firstly, incident shock wave is transmitted in the axial direction and are reflected on a wall surface after meeting a first segment of folding surface AB, the mach number of the incident shock wave is 1.6, a starting wedge surface angle of the first segment of folding surface is 25 degrees, the incident shock wave is reflected on the wall surface when meeting a second segment of folding surface BC, the mach number of the incident shock wave is 1.913, the starting wedge surface angle of the second segment of folding surface is 35 degrees, the incident shock wave is reflected on the wall surface when meeting a third segment of folding surface CN, the mach number Mw 2 of the incident shock wave is 2.31, and the starting wedge surface angle of the third segment of folding surface is 30 degrees. The strength of the shock wave at the outlet of the circular passage is enhanced by 68.1% compared with that of the initial incident shock wave, compared with a direct folding 90-degree sudden folding type circular passage, the focusing moment of the shock wave is advanced for 8 microseconds, and the peak pressure and the peak temperature caused by the focusing of the shock wave at the bottom of a camber concave cavity are improved by 76.5% and 32.1%.