The invention relates to a virus-free rapid propagation method of purple sweet potato Zhezi No. 1, comprising the specific steps of (1), stripping stem-tip merismatic cones from purple sweet potato seedlings under aseptic condition, and inoculating to a stem-tip induction medium; (2), in an artificial climate box, subjecting the step tips inoculated to the medium to variable temperature thermal treatment and cultivation and then to cultivation in a normal environment; (3), selecting robust purple sweet potato aseptic seedlings, cutting to obtain stem segments with uniform size, axillary buds and zero root knots, inoculating to a multiplication medium, culturing in the artificial climate box, selecting rooted purple sweet potato seedlings, exercising them in a greenhouse, washing the medium at roots, and transplanting to sandy loam for growth. In detoxification of purple sweet potato Zhezi No. 1, stem-top culture and variable temperature thermal treatment are combined, virus-free culture time is shortened, detoxification efficiency is improved, detoxification technology for purple sweet potato Zhezi No. 1 is optimized, and a stable and efficient technical system for virus-free rapid propagation of purple sweet potato Zhezi No. 1 is established.