In this work attention has been paid to polyisoprene-nanostructured carbon composites (PNCC) as prospective piezoresistive materials for use in pressure sensing applications as well as tactile elements for robotics. Our recent research approved that vulcanization process has an important role in the chain of processes when producing composite with necessary mechano-electric properties. In the current article we present an original attempt to investigate the development of percolative electroconductive structure of PNCC during vulcanization. The “in-situ” measurements of electrical resistivity have been performed to evaluate the development of percolative carbon black structure in PNCC directly during the vulcanization process. The measurements of piezoresistive effect for samples with different durations of vulcanization time have been made. The samples have been studied using SEM and dielectric spectroscopy. To perform SEM analysis the samples were frozen in liquid nitrogen and then fractured. Four different processes that affect the formation of percolation structure of high structure carbon black (HSCB) in PNCC during vulcanization phase have been identified.