Polymer based 3D printings are generally generated from the melt fluids or gels instead of polymer solution. Inspired by continuous wet-spinning of polymer fiber, we explored a new polyvinyl formate (PVFm) printing ink which was directly coagulated by water and mold into designed 3D elastic architectures layer-by-layer. The degree of esterification (DE), chemical structure, morphology, and mechanical properties of PVFm were all investigated. Furthermore, 3D PVFm was coated by polypyrrole (PPy) via in-situ polymerization to fabricate wearable flexible electronic sensors. The relative resistance changes and sensitivity of PPy@PVFm on monitoring physical strain and pressure were characterized. Results show that PPy@PVFm could stably and sensitively recognize human body activities through relative changes in resistance in a wide range of linear relationship. Therefore, a new protocol is readily to realize a strategy of 3D wet-spinning printing and wearable flexible electronic sensors.