The isothermal section of Ni-Cr-Mo ternary system at 1358 K was determined by means of diffusion triple and electron microprobe analysis. The results indicate that one binary intermetallic of NiMo is formed in Ni-Cr-Mo ternary system at 1358 K. In this diffusion triple, Cr and Mo formed into a continuous solid solution, and Ni and (Cr,Mo) formed into a finite solid solution. No ternary compound was observed. One three-phase region of Ni+NiMo+(Cr, Mo) exixts in the isothermal section of Ni-Cr-Mo ternary system at 1358 K.