Direct growth of large area uniform high quality graphene films on insulating substrates is very important for graphene-based devices. Here we report a facile approach to directly fabricate uniform and large area bi-layer graphene films on MgO(100) substrates by chemical vapor deposition, without the aid of any metal catalysts. Raman spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy are used to characterize the synthesized graphene films. Raman mapping indicates that the graphene films are large area uniformity. The mobility of these directly grown graphene films is 130 cm(2)/(VS) and they may have potential applications in electronic devices, sensors, conductive films, etc.