The invention discloses a preservation method of rose alternaria panax. The method comprises steps of separation of the rose alternaria panax, purified culture, activity detection, propagation, preservation and restoration. The propagation and preservation of the rose alternaria panax comprises the following steps: when the detected value of the activity of cultured spores is larger than or equal to 90%, inoculating spores which are regulated to 1*10<5>-2*10<6>/ml in a disinfected rose variety or wild variety of detached leaf sensitive to rose black spot; culturing for 7-14 days in a moisture-retaining culture dish at the condition that the indoor light intensity is 1800lx to 3200lx, the light period is 10-16 hours, the dark period is 8-14 hours, the relative humidity of air is 90% to 100% and the room temperature is 18 to 28 DEG C; taking out the detached leaf, rapidly freezing in liquid nitrogen, and then preserving in a refrigerator at the temperature of -70 to -80 DEG C. The preservation method disclosed by the invention has an effect that the activity of the rose alternaria panax is still above 90% and the pathogenicity of the rose alternaria panax is as high as 100% after the preservation period of the rose alternaria panax is prolonged to 3 years.