Bamboo leaf dye and extraction method and application thereof

The invention discloses a bamboo leaf dye and an extraction method and application thereof. The method comprises the following steps of: extracting twice by taking 0.25 to 0.3mol/L solution of sodium hydroxide as an extractant, wherein the solid-liquid ratio of the solution of sodium hydroxide is 1:35-1:40, the amount of the extractant used at the first time is 60 percent based on the total usingamount of the extractant, the filter residue is extracted for the second time, the amount of the extractant used at the second time is 40 percent based on the total using amount of the extractant, the extracting temperature is 100 DEG C every time and the extracting time is 50 to 60 minutes every time; and mixing the extracting solution obtained by extracting twice to obtain the product serving as a pure silk coloring agent. In the extraction method, extraction can be conveniently performed, more colored components can be extracted from plants by adopting alkaline aqueous solution, and the prepared dye has good effect of dyeing the pure silk.