We have demonstrated organic thin-film transistor devices on synthesis paper of polypropylene (PP). All the fabrications are in solution-based processes except electrodes. As a barrier and smoother layer, photosensitive epoxy, 5μm-thich was coated on the paper substrate by using slit die coating. Polyvinyl phenol (PVP) was mixed with poly (melamine-co-formaldehyde) methylated, filmed by spin coating and ultraviolet (UV) cross linked to provide the gate dielectric layer. Using poly (3-hexylthiophene) as an active layer, a high-performance organic transistor with field effect mobility up to 0.006 cm2/ V s and an on/off ratio of 50 can be achieved. For the applications in flexible and disposable electronics, to built organic transistors on a cheap synthesis paper substrate can extremely lower the cost.