The major etiologies of gout and kidney stone formation are similar hyperuremia, which is caused by unbalanced uric acid production/exertion. And gout is one of the important risk factor that promotes kidney stone formation. It's worth noting that crystals retension/aggregation is the early stage of stone formation. However, the mechanism between gout and crystalluria remains unclear. Our previous studies found good correlation between auto-fluorescent crystals and urolithiasis. Higher proportion of auto-fluorescent crystalluria in gout patients were also noted. It this paper, we demonstrated characterization of auto-fluorescent urinary crystals in gout patients by micro-Raman system and laser confocal microscopy. Our purpose is to figure out the mechanism among gout flare, urolithiasis and auto-fluorescent crystal retention. And the results supported that fluorophore inside the crystals may be a powerful indicator for crystals retention. Further studies are required to validate our hypothesis.