According　to　polychromatic　sets　theory,　the　conceptual　model　of　jig　and　fixture　was　established.　Element　combination　map　of　a　jig　and　fixture　conceptual　design　was　built　through　analyzing　assembly　relation　and　reciprocity　of　each　element,　then　a　polychromatic　map　was　established.　In　addition,　all　the　paths　and　structure　element　groups,　which　fulfilled　the　restricted　conditions,　were　gained　by　the　algorithm　of　polychromatic　sets　theory.　Compared　with　other　design　methods,　the　method　with　polychromatic　sets　is　very　convenient　to　program　and　describe　by　computer.　At　last,　an　example　was　presented　to　explain　the　theory.