The invention provides an integrated microstrip circulator, belonging to the electronic technical field. The integrated microstrip circulator comprises a metal bottom electrode on a microwave medium substrate, a nanowire ferromagnetic composite medium, an insulating layer and a Y-junction of the microstrip circulator, wherein the nanowire ferromagnetic composite medium is compounded by a ferromagnetic metal nanowire and aluminum oxide, the aluminum oxide has a nanometer grade porous structure, and the ferromagnetic metal nanowire is filled in the nanometer pores of the aluminum oxide by the electroplating process. The preparation method comprises the following steps: depositing the metal bottom electrode and a metal aluminum film on the microwave medium substrate; performing secondary anode oxidizing treatment on the metal aluminum film; filling the ferromagnetic metal nanowire in the nanometer grade pores of the aluminum oxide by the electroplating process; and manufacturing the required Y junction for the circulator. In the method, the nanowire ferromagnetic composite medium compounded by the ferromagnetic metal and the porous aluminum oxide is adopted as an automatic biasing magnetic medium of the microstrip circulator, the work efficiency of the microstrip circulator can be improved, and the volume and the weight of the circulator can be reduced; and the preparation process of the microstrip circulator can be compatible with the microwave integration circuit process.