A light source from a neodymium-doped yttrium aluminium garnet laser (1064 nm) was used to excite the A3 iron plate to produce plasma and release UV light for the rapid photocatalytic degradation of methylene blue (MB) dye. The 30 nm anatase TiO2 nanoparticles were used as the photocatalysts. Plasma effectively degrades organic matter under optimal conditions: (10 mg/L MB, 2 g/L TiO2, 50 ml/L H2O2, pH = 10, and P = 70 mW); the degradation efficiency is related to the UV light source (200 nm - 400 nm) produced by plasma sonoluminescence. The effect of the initial dye concentration, catalyst dosage, laser energy, and pH value, on the degradation of dyes was studied using UV–vis spectrophotometry. Ion chromatography confirmed the mineralisation of methylene blue (MB). The results showed that laser-induced plasma (LIP) photocatalysis effectively degrades MB.