The lack of strong binding mechanism between nanomaterials severely restricts the advantages of evaporation-driven hyhrovoltaic effect in wearable sensing electronics. It's a challenging task to observably improve the mechanical toughness and flexibility of hyhrovoltaic devices to match the wearable demand without abandoning the nanostructures and surface function. Here, we developed a flexible tough PAN/Al2O3 hydrovoltaic coating with both good electricity generation (open circuit voltage∼3.18 V) and sensitive ion sensing (2285 V M−1 for NaCl solutions in 10−4-10−3 M) capabilities. The porous nanostructure composed of Al2O3 nanoparticles is firmly locked by the strong binding effect of PAN, giving a critical binding force 4 times than that of Al2O3 film to easily deal with 9.92 m s−1 strong waterflow impact. Finally, skin-tight and non-contact device structures were proposed to achieve wearable multifunctional self-powered sensing directly using sweat. The flexible tough PAN/Al2O3 hydrovoltaic coating breaks through the mechanical brittleness limitation and broadens the applications of evaporation-induced hydrovoltaic effect in self-powered wearable sensing electronics.