For the first time, the temperature dependences of the electrical resistivity and magnetization of the Cd48.6Mn11.4As40 nanocomposite were measured in the temperature range of 10–350 K. It is shown that the electrical properties of Cd48.6Mn11.4As40 are associated with spin polarization of intrinsic electrons in the Cd3As2 matrix by spin-polarized electrons injected into it from ferromagnetic MnAs nanoclusters. With an increase in the magnetization of the entire sample, the angle between the magnetization directions of individual nanoclusters decreases and the spin-polarized current increases. Furthermore, an increase in the concentration of intrinsic carriers in the matrix leads to an increase in the spin-polarized current. This concept is also confirmed by measurements of current–voltage characteristics (CVCs) at voltages of up to 5 V at temperatures both below critical temperature Tcg = 241 K of cluster glass formation (at 77 and 172 K) and above it (at 273.15 and 373.15 K), which exhibit an increasing deviation from the ohmic behavior with an increase in the stress. This means that the greater the spin polarization of intrinsic electrons in Cd3As2 due to an increase in the injection of spin-polarized electrons from MnAs with an increase in the voltage, the higher the current.