PeneloPET is a PET-dedicated Monte Carlo simulation toolkit, which is based on PENELOPE. This article describes the characteristics and the general process of PeneloPET simulation. Then we compare the simulation results of PeneloPET and GATE to model the GE Healthcare eXplore Vista microPET system respectively, including sensitivity and noise equivalent count rate. The results show that PeneloPET simulation data corresponds with the data from real scanners and GATE simulation, and proves PeneloPET is an accurate toolkit for PET simulation.