负载弦指的是在均匀的弦上固定一些小质量块得到的非均匀弦.弹性波在弦上传播过程中遇到质量块发生反射和 透射，类似量子力学中的几率波在势阱或势垒处的行为.借助这个类比，我们使用负载弦演示了量子力学中的能级回避交叉、 周期势场中的能带结构以及随机系统中本征态的局域化现象，使得量子力学中比较难理解的概念得到直观形象的展示.

Loaded string is constructed by bonding some masses on a homogeneous string. When the elastic wave travels on the string meet one of the masses，it will partly penetrate the mass and partly reflect back，this is similar to the action of a potential barrier or well on quantum probability wave. Based on this similarity，we demonstrate in this paper the avoided crossing of energy levels，energy band in periodic structure and localization of eigenstate in random structure by the dynamics of a loaded string. We hope this experiment that can help students to understand those intriguing quantum phenomena.