Polycrystalline Mn1.1Fe0.9P0.76Ge0.24 was prepared by mechanical alloying and spark plasma sintering. Neutron diffraction was used to determine the structure of the title compound, and its nuclear and magnetic structures were refined using the Rietveld method. It is found that temperature and magnetic field can induce phase transition between the paramagnetic and the ferromagnetic phases in the material, and the paramagnetic and ferromagnetic phases have very distinct crystal structures and different Ge contents.