摘要： 预期违约与不安抗辩制度的界分遵循的是一个简单的原则：债务人将来确定不履行，成立预期违约，债权人可于期前解除合同并主张违约救济；债务人将来不履行的可能性程度较高但尚非确定，则适用不安抗辩制度。为便于终结行使给付拒绝权后可能出现的悬而未决状态，应赋予债权人以请求提供充分保障之权，若适当期间经过而对方未提供，可确认不履行的可能性程度提高，成立新的预期违约形态。不安抗辩与预期违约由此形成衔接。

关键词: 不履行, 可能性程度, 界分, 衔接

Abstract: The demarcation of anticipatory breach and insecurity defence follows a simple principle: if the obligor willcommit non-performance surly in future, the obligee can terminate the contract and seek remedies for performanceof the obligor; if possibility degree of the obligor's non-performance in future is considerably high but not cer-tain, then applies insecurity defence, and contract relationship is maintained. In order to end unresolved state,the obligee should be granted right to demand adequate assurance, if the other party does not provide such assur-ance within reasonable time, then constitues a new type of anticipatory breach and two institutions join here.

Key words: Non-performance, Possibility Degree, Demarcaton, Joining