Recovery　processes　of　secondary　resources　usually　encounter　problems　because　of　the　diverse　compositions　of　wastes.　To　enhance　the　applicability　of　traditional　hydrometallurgical　process　toward　secondary　resources,　the　adjustment　of　components　is　necessary.　In　traditional　hydrometallurgical　separation,　precipitation　and　complexation　are　extensively　used.　However,　their　combination　as　a　specific　metal　separation　method　has　not　yet　been　studied　in　detail.　This　approach　is　very　promising　for　solving　problems　caused　by　changeable　components　during　recycling　processes　of　secondary　resources.　This　paper　reviews　the　effects　of　precipitation　and　complexation　in　metal　separation　processes,　and　a　metal　separation　method　system　of　＂complexation-precipitation＂　developed　to　adjust　the　components　of　secondary　resources　is　introduced.