To solve environmental and energy related issues through photocatalytic technology requires highly efficient, stable and eco-friendly photocatalysts. Gold nanoparticle decorated chemically exfoliated two dimensional MoS2 nanosheet exhibits promising potential in field of photocatalysis for degradation carcinogenic brilliant green dye molecule. The Au-MoS2 nanocomposite degrades this dye much faster rate than bare MoS2 under visible light, improvement of photocatalytic performance is ascribed due to the effective suppression of the recombination of charge carriers. This Au-MoS2 nanocomposite can be used for industrial purposes for water purification.