A printing and dyeing wastewater treatment and reuse apparatus includes a coarse filter, a regulation pool, a hydraulic sieve, a desulfurization pool, a nanocatalytic electrolyzer, a flocculation pool, a flocculation tank, a settling pool, a flotation device, a biochemical pool, a secondary settling pool, a secondary nanocatalytic electrolyzer, a fine filter, a compressor, a nanomembrane assembly, and a recycling pool. Also provided is a printing and dyeing wastewater treatment and reuse method including steps of desulfurization, nanocatalytic electrolysis, flocculation, biochemical treatment, secondary catalytic electrolysis, filtration, and separation by membrane. The invention allows high CODCr removal rate, reduced chemical agent consumption, reduced sludge formation, thorough treatment, and high water reuse rate.