若尔当曲线定理是拓扑学最著名的定理之一，也是数学中一个非常重要的定理，其定理本身简单明了，显而易见，但其定理的证明却很复杂，以至数学教材中往往将此定理的证明忽略不讲，证明的主要想法就是将曲线化为折线，证明若当闭折线是成立的，然后再用折线去逼近曲线，而折线的证明相比曲线就可以简单得多，在此，我整理了几个若当闭折线定理比较简单的证明方法，根据奇偶性来证明若尔当闭合折线定理，以及运用归纳法来证明若尔当闭合折线定理。

Jordan curve theorem is one of the most famous theorem in topology, the represenstation of itself is simple, also obvious, but the proof of the theorem is very complex.The most textbooks in mathematics do not give the proof of the theorem.The main idea of the proof in this article isto change the Jordan curve to broken line, The Jordan curve theorem canbe proved by approximating Jordan curve by broken line, therefore, the Jordan broken line theorem are given by choosing the proofs in the references. One of them is the induction of mathematics, the other is the method of old-even.