A safe and easy way to perform bio-tattoo by DIY tanning was promoted. Dihydroxyacetone (DHA), the most effective additive for sun-free tanning as an alternative to UV tanning, was biosynthesized in situ from glycerol by designed biomolecular machines. The coupling multi-enzyme system, glycerol dehydrogenases (GDH) and NADH oxidase (NOX) enzyme nanoring, catalyzed the biosynthesis of DHA from glycerol with cofactor regeneration. Multi-enzyme nanorings were formed with the Ni2+ and bis-His coordination of GDH-NOX fused enzymes, which enhance enzyme activity and stability. The efficiency of biomolecular machines was adjusted with the concentration of NADH and glycerol. The coloration levels from light to dark correspond with the DHA percentages. Various patterns and letters can be printed on the skin using packs, providing a safe, painless and easy way for DIY bio-tattoo.