The invention provides a method for comprehensively utilizing copper slag. The method comprises the following steps: 1) stirring the copper slag by using nitrogen, so that copper matte particles are collided to grow and are settled and separated; 2) spraying coal dust, quick lime and oxygen enriched air into the copper slag after the copper matte particles are separated, and reducing to extract iron; 3) adding additives into the residues after the iron is extracted and controlling the temperature of the melt mixture of the residues and the additives to be 800 to 1,700 DEG C; and 4) preparing inorganic fiber from the melt mixture by a blowing or centrifuging method. The inorganic copper slag fiber is prepared from the residues on the basis of performing depletion, copper extraction, reduction and iron extraction on the hot copper slag in a furnace, so that high efficiency non-waste utilization of the copper slag is realized. The fiber obtained by the method is excellent high temperature resistant fiber and has wide prospect in the field of industrial fire resistant insulation.