In traditional electronic devices, the electronic charge is manipulated to realize different functions. The fascinating control of electronic spin in conventional semiconductors increases the probability of occurrence of spin-dependent transport properties. Herein, the injection of electronic spin into a Si wafer with in-plane geometry was achieved by Fe3O4, which acted as a spin injector. At high temperatures, the resistivity of Fe3O4 is far less than that of a p-Si wafer. Moreover, above 190 K, the current-voltage (I-V) characteristic and magnetoresistance (MR) of the proposed heterostructure are dominated by the intrinsic properties of a polycrystalline Fe3O4 film, and the in-plane current flows in the Fe3O4 layer. Due to the increased resistivity of Fe3O4 at low temperatures, the in-plane conductive channel gradually switches from Fe3O4 to Si. The spin injection from Fe3O4 results in a spin-polarized space charge region in p-Si. The heterostructure shows an MR of up to -76.1% at 90 K due to the spin-dependent transport of electrons in p-Si. With a further decrease in temperature, the I-V characteristic of the heterostructure shows negative differential resistance below 80 K due to band bending at the Fe3O4/SiO2/p-Si interface.