The invention provides a steel slag deep treatment technology. The steel slag deep treatment technology comprises steel slag crushing, screening and magnetic separation. Steel slag vibration feeding,first-time sorting, second-time sorting and magnetic separation are included, crushing and circular screening conducted among the above procedures are further included, and 99% or above of metal is economically and efficiently recycled through circulating of three-pass crushing, three-pass screening, two-pass magnetic separation, one-pass cleaning and twelve-point dust removal. The grain size standard of tailings for sales is 0-5 mm, the metal iron content is 1% or below, and renewable resources are sufficiently recycled. The maximum steel slag comprehensive utilization value is actually achieved, and zero discharging of tailings is achieved.