The invention discloses a P-type doping method for a semiconductor layer of an organic field effect transistor and the prepared organic field effect transistor, and the method comprises the steps: dissolving 2, 3, 5, 6-tetrafluoro-7, 7 ', 8, 8'-tetracyanodimethyl p-benzoquinone (F4-TCNQ) in an orthogonal solvent of the organic semiconductor layer to serve as a P-type doping agent; the method comprises the following steps of: preparing an organic semiconductor layer film, spin-coating the organic semiconductor layer film on the spin-coated organic semiconductor layer film in an air atmosphere, and activating doping through rapid thermal annealing, so that the problems caused by jump transmission and coulomb traps in charge transport are solved, the threshold voltage is reduced, and the switch ratio is increased. For the P-type field effect transistor, the P-type doping enhances the hole transport, effectively improves the saturation current, and inhibits the electron transport, so that the power consumption is reduced when the transistor is closed. The doping method is operated based on a solution method, is simple in process and low in preparation cost, can be suitable for large-scale production, and has a very good prospect in application of flexible and portable electronic equipment.