The invention discloses a recycling method for metal silver in sliver-containing waste liquor by utilizing black silicon piece reaming waste liquor and a waste liquor recycling method for a photovoltaic black silicon piece production line comprising two kinds of waste liquor, and provides a rotary electrode used during waste liquor electrolysis. The recycling method for silver-containing waste liquor and strong acid waste liquor and the waste liquor recycling method for the photovoltaic black silicon piece treatment waste liquor comprising two kinds of waste liquor realize recycling noble metal silver in waste liquor, so that elemental sliver, calcium fluoride with co-production purity being 80-85%, calcium nitrate with purity being 90-95%, and ammonia water with concentration being 20%-30% are obtained; and evaporated water and prepared ammonia water can be recycled for producing, so that efficient utilization for materials in waste liquor is realized, and therefore, comprehensive operation cost of waste liquor treatment can be reduced, and environmental pollution is avoided.