Abstract: In order to improve the detoxification technology of Dahlia pinnata， acquire highquality virusfree seedlings， Dahlia pinnata infected with dahlia mosaic virus (DMV)， cucumber mosaic virus (CMVD2) and tobacco mosaic virus (TMV) were used as experimental material， the effects of heat treatment， chemical treatment methods combined with stem tip culture on detoxification were studied in this paper. The results of enzymelinked immunoassay (ELISA) showed that stem tip in combination with heat treatment could effectively remove the DMV and CMVD2， and virusfree rate was 747% and 669% respectively， but it could not remove TMV effectively， while the removal rate of three kinds of viruses was 106%. Stem tip method combined with chemical treatment could effectively remove the DMV， CMVD2 and TMV， and virusfree rate was 831%， 805% and 771% respectively， while virusfree rate of all the three was 243%．

Key words: Dahlia pinnata, stem tip, heat treatment, chemical treatment, detoxification