The ternary Si-P-Ni phase diagram between 0 and 66.7at.% was investigated by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray diffraction (XRD) on the equilibrated alloys at 1073 K.Twenty five three-phase regions were identified to exist at this isothermal and seven ternary compounds were observed.And three new ternary compounds were observed in this work.