Amentotaxus argotaenia (Hance) Pilger is one member of Amentotaxus in Taxaceae. Due to the close genetic relationship between A. argotaenia and Taxus sp., some researchers thought that taxol could be synthesized in A. argotaenia and testified this hypothesis using HPLC method. This conclusion was just reached based on the retention time of the peak in the extract of A. argotaenia corresponding to that of the taxol standard, but not from any mass spectra data. In this study, we analyzed the extraction of the stems and leaves of A. argotaenia with LCMS, and found that there was no taxol in the extraction. In order to prove our hypothesis, AarTSL1 gene was isolated and cloned by using the taxadiene synthase of Taxus baccata to TBLASTN the transcriptome of A. argotaenia. Functional analysis of AarTSL1 with prokaryotic expression showed that the AarTSL1 protein cannot catalyze GGPP (geranylgeranyl pyrophosphate) to taxadiene, key intermedia in taxol biosynthesis pathway. Taking together, our chemical and molecular biology evidence proved that A. argotaenia cannot product taxol. Our results will be helpful to the research work on the taxonomic study of A. argotaenia.