Lanthanide polyhydrides, which have attracted the attention of researchers, are considered as a potential candidate material for high-temperature superconductivity. Especially, it is reported that N-doped LuH3 exhibits near ambient superconductivity recently. It has attracted attention to room temperature superconductivity of ternary lutetium hydride at near ambient pressure. Here, we constructed a LuNH3 (N-doped LuH3) compound to predict the crystal structural at relatively low pressures. We found a stable ternary lutetium hydride LuNH3 structure with a tetragonal P4mm phase under 5 GPa. In addition, our T_c calculations show that the P4mm LuNH3 structure does not exhibit superconductivity down to 0.3 K at near ambient pressure due to the H atoms hardly contribute to acoustical phonons.