Phase relations of Ti-Mn-Zr ternary system at 1020 and 800°C have been investigated mainly by metallographic observations, x-ray diffraction and electron microprobe analysis.A new ternary compound named K was detected, which shows a remarkable homogeneity range both at 1020 and 800°C. The isothermal section at 1020°C contains 8 single-phase regions, 13 twophase regions and 6 three-phase regions, while the isothermal section at 800°C consists of 9 single-phase regions, 15 two-phase regions and 7 three-phase regions. The continuous solid solution (Ti,Zr)Mn 2 shows a wide homogeneous range both at 1020 and 800°C, and the phase TiMn 4 exists at 1020°C and disappears at 800°C.