As is well known, most natural diamonds usually contain not only aggregated nitrogen up to thousands of ppm but also hydrogen. Therefore, the studies of nitrogen and hydrogen impurities in a diamond are of interest for improving the physical properties of a diamond and solving the problems about natural diamond genesis. From this point of view, in this paper, we choose C3N6H6 powders as a nitrogen and hydrogen source and select high-quality seed crystals with {100} facets as the growth facets. The effects of nitrogen and hydrogen co-doped on {100}-oriented single diamond in the NiMnCo-C system at pressures ranging from 5.5 GPa to 6.2 GPa and temperatures of 1280-1450 ℃ are investigated. Experimental results show that both pressure and temperature, which are the synthesis conditions, increase with the increases of nitrogen and hydrogen content in diamond-growth environment, and the V-shape region of diamond-forming moves up. From the obtained Fourier transform infrared spectra, we notice that there is a significant change of the nitrogen concentration in the synthesized diamond with increasing the nitrogen and hydrogen content in the diamond-growth environment. We calculate the nitrogen concentrations in those diamonds and the results indicate that the highest concentration of nitrogen is up to 2000 ppm. Meanwhile, we notice that the hydrogen associated infrared peaks of 2850 and 2920 cm-1 are gradually enhanced, which shows that both nitrogen and hydrogen are successfully co-doped into the diamond. Scanning electron microscope micrographs show that the {111} face is elongated and has triangulated textures appearing on the surface with nitrogen and hydrogen co-doped into the diamond. This result indicates that the synergistic doping of nitrogen and hydrogen has a great influence on the morphology of {100}-oriented single diamond. From the obtained Raman spectra, we find a shift towards higher frequency of the Raman peak from 1330.23 cm-1 to 1330.40 cm-1 and the full width at half maximum increases from 3.12 cm-1 to 4.66 cm-1 with increasing the concentrations of nitrogen and hydrogen in diamond-growth environment. This is the first report about nitrogen and hydrogen co-doped on 100-oriented single diamond by far. This work can provide a new method to study the influences of nitrogen and hydrogen impurities on diamond synthesis and it will help us to further understand the genesis of natural diamond in the future.