Abstract: To discuss utilizing the Geant4 Application for Tomographic Emission(GATE) software to simulate the imaging process of Positron Emission Tomography(PET),as well as the related image reconstruction.The configuration and calculation of script parameters for several important components in the GATE simulation are introduced,which includes the structure configuration of a PET scanner,the setting of the object's the spatial structure and activity distribution,as well as the determination of detector performance parameters for γ photon detections.The generation of sinogram data from photon counts and the following image reconstruction are also described.As an example,the imaging process of Inveon micro PET for small animals produced by Siemens is simulated and desirable images are obtained.