中文摘要：

给出了三体223Bell对角态纠缠判定的一个必要条件和333Bell对角态纠缠的充分条件,进一步研究了333Bell对角态纠缠与密度矩阵部分转置的关系以及Bell对角态负性的数学表达式.

英文摘要：

A necessary condition of entanglement for tripartite 223 Bell diagonal states and a sufficient condition of entanglement for 333 Bell diagonal states are presented.Moreover,the relation between entanglement of 333 Bell diagonal states and partial transpose of density matrix is investigated.And an analytical expression of negative for Bell diagonal states is presented.