The invention belongs to the field of post-treatment of titanium dioxide, and particularly discloses a zero emission process for treating titanium chloride slag. The process includes the following steps of (1) alkali leaching; (2) solid-liquid separation; (3) secondary precipitation; (4) micro-filtration/ultra-filtration membrane filtration; (5) primary membrane purification; (6) membrane concentration; and (7) secondary membrane purification. In the process, the purpose is to treat heavy metal ion impurities in the titanium chloride slag and recycle chlorine ions, and solid waste slag is converted to harmless solid to be reused for bricks, tiles, cement and the like of building materials; concentration and purification are performed through a membrane separation integrated process so thatlight salt brine used for the chloro-alkaline industry can be obtained for use; due to implementation of the process, valuable resources in the titanium chloride slag are recycled and utilized, moreimportantly, the titanium chloride slag serious in pollution to environment protecting is completely and thoroughly treated, the bottleneck that the chlorination method solid waste slag is difficult to treat is broken through, a process for producing titanium dioxide in a chlorination method gets one important step in environment protecting direction, and obvious advancement is achieved.