NiNH$_{4}PO_{4}$ was Prepared from waste Ni catalyst used in hydrogenation of oil and fat, NiNH$_{4}PO_{4}$ was calcined at different temperature respectly 800, 1000, 1100$^{circ}$C to prepare Nickel yellow. The results from this experiment are summerized as follow: 1) Nickel yellow formed at 1100$^{circ}$C was most clearness yellow color from color analyzer data. 2) Nickel yellow was consist of ${alpha}-Ni_{2}P_{2}O_{7}$, $Ni_{3}(PO_{4})_{2}$ from X-ray diffraction analysis. 3) The endothermic pick at 100$^{circ}$C and exotherwic pick about 1050$^{circ}$C on calcination of NiNH$_{4}PO_{4}$ were checked in DTA (difference thermal analysis data)