Natural rubber (NR) is an essential industrial raw material predominantly sourced from Hevea brasiliensis, yet its production is constrained by geography. Taraxacum kok-saghyz (TKS) is a promising alternative source, but its NR yield is limited by low NR content. Here, we integrate metabolomic and genetic intervention to uncover and reprogram the metabolic basis of NR accumulation. Widely targeted metabolite profiling across six Taraxacum germplasms revealed a strong negative correlation between NR content and fructan-type saccharides. We suppressed sucrose:sucrose 1-fructosyltransferase (1-SST), the entry and rate-limiting enzyme in fructan biosynthesis. RNAi lines exhibited a significant decrease in the content of inulin, a stable storage fructan, alongside a notable increase in root sucrose and the upregulation of the sucrose transporter SUT1. Concurrently, the NR content increased fourfold to almost 30% within three months, accompanied by elevated expression of key rubber transferase complex components and reduced steady-state levels of prenyl diphosphate precursors in latex. Metabolic shift towards the production of terpenoids and phenylpropanoids, alongside reduced levels of auxin, cytokinin, and jasmonate, coincided with changes in root growth and an increased laticifer index. These results establish that 1-SST acts as a carbon-flux switch between fructan and NR pathways, providing a practical strategy to boost NR production in TKS.