The invention provides a Zn in-situ doping P type hexagonal boron nitride film and a preparation method thereof, and belongs to the technical field of semiconductor material preparation and semiconductor doping. According to the method, a high-purity hBN target, a high-purity Zn target and a cleaned substrate are put into a magnetron sputtering growth chamber; a radio frequency magnetron double-target co-sputtering technology is used; Zn impurities are doped in situ in the hBN film growth process; after the growth completion, the film is subjected to in-situ annealing in the N2 atmosphere; thefilm is cooled to the chamber temperature under the N2 gas protection, so that the Zn in-situ doping P type hBN film is obtained on the substrate. The method is simple; the cost is low; safety and reliability are realized; the toxicity and harm do not exist; the doping concentration can be controlled through regulating the target distance and the sputtering power of the Zn target; the B atom lattice point position can be easily occupied by Zn in the hBN film and has the lower forming energy and smaller impurity activation energy as the substituting impurities, so that the Zn doping P type hBNfilm with lower resistivity can be obtained; the performance is stable.