We propose the use of double photon coincidence events resulting from cascade decay of certain radioactive nuclides to increase the signal to background ratio and its spatial resolution in a 3-D Compton imaging system. The Time-of-flight (TOF) technique could be applied to ensure a better image quality on the third direction with utilization of photon arrival time. Geant4 simulation is performed to evaluate the design of TOF double photon Compton imaging. The result shows that the TOF technique can greatly improve the image quality. The FWHM value has decreased by more than 60% in the reconstructed 3D image on the depth direction.