Dyeing method of double mercerizing sulfur black

The invention discloses a dyeing method of double mercerizing sulfur black. The dyeing method comprises the steps of dyeing, recycling, washing for fixation and brittleness prevention. Heat preservation is conducted at the temperature of 98 DEG C, the pretreated double-mercerized cloth is soaked in a dye vat, dyeing components in the dye vat comprise sulfur black dye, an alkali-resisting penetrating agent, caustic soda and an environment-friendly reducing agent compound, stirring and heating are conducted, it is guaranteed that the sulfur black dye is completely reduced into a leuco body, then the double-mercerized cloth is put into the dye vat, and fast washing enzyme is added in the operation process; the environment-friendly reducing agent compound is formed by uniformly mixing vitamin C and reducing sugar in a powder mixer according to the mass ratio of 2: 8; the reducing sugar is mixed cane sugar and glucose in a mass ratio of 5: 5; the environment-friendly reducing agent compound composed of vitamin C,