Abstract In the present work, the poly (vinylidene fluoride) composite filled with the lead zirconium titanate (PVDF/PZT) was numerically investigated focusing on the improvement of piezoelectric performance parameters. With a multi-scale simulation strategy, effects of the PZT fillers’ orientation and length on the electrical outputs of the piezoelectric energy collectors buried in the roads were systematically examined. Specifically, at the micro-scale, based on our previous research results, Comsol Multiphysics connected with Matlab was utilized to create the unit cell of piezoelectric composites. The simulation results showed that parameters of PZT nano-fillers greatly affect the piezoelectric coefficients. For the macro-scale simulation, a road energy collector with innovative symmetrical cantilever structure was designed, with piezoelectric constants obtained at micro-scale simulation as inputs. The correlation between the output voltage of the energy-collector and PZT parameters (i.e., orientation and length) was successfully developed by applying the vehicle’s axle-load. This work provides a way for tailoring the piezoelectric performance of the macro components (i.e., sensors) through adjusting the states of the fillers inside the piezoelectric composites.