The phase equilibria in the Zr–Cu–Ni ternary system are investigated combined with X-ray diffraction, electron probe micro-analysis and differential scanning calorimetry. Two isothermal sections of the Zr–Cu–Ni ternary system at 1 000 °C and 1 100 °C are experimentally established. Most of the binary intermetallic compounds, e. g. Zr7Ni10, ZrNi, ZrNi5, Zr14Cu51, and Zr2Cu9, show a remarkable ternary solubility. A new ternary compound named τ3 (Zr31.1–30.7 · Cu28.5–40.3Ni40.4–29.0) is detected at 1 000 °C and dissolved at 1 020 °C because the nearby large liquid phase field further expands. The newly determined phase equilibria will provide important information for both thermodynamic assessment and alloy design of Zr-based metallic glass.