Researches　conducted　for　Mind　mapping　application　in　primary　education　semantic　ontology,　while　considering　unique　characteristics　of　primary　education,　found　there　were　rare　widely　used　ontology　libraries　and　few　connections　between　ontology　libraries　for　information　sharing　and　reuse.　In　addition,　primary　semantic　ontology　library　lack　precise　definitions　of　the　semantics.　This　paper　proposed　a　solution　based　on　cluster　structure　derived　from　mind　mapping　by　providing　logical　description　of　the　ontologies　to　precisely　define　semantics;　Meanwhile,　tags　were　adapted　to　associate　different　ontologies　to　form　ontology　library.