A novel tetraphenylethylene derivative tethered with polyhedral oligosilsesquioxane nanocages (TPE-POSS) was designed and synthesized as turn-on fluorescent sensor for detection of F−. The aggregation-induced emission (AIE) property, self-assembly behavior and detection mechanism of the complex were then elucidated by UV–vis absorption spectra, photoluminescence spectra and dynamic light scattering experiments. The results reveal that POSS nanocages can collapse due to the Si–O bond cleavage with the present of F−. The POSS nanocages collapse then trigger the AIE activity of TPE luminogens, endowing TPE-POSS with excellent turn-on detecting ability, high selectivity and sensitivity to F−, with a detection limit as low as 1.66 × 10−7 M.