光保存系指以光电工程之方法，将数据保存于光学可读的介质上，以进行数据的保存。电脑所使用的唯读记忆光盘以及蓝光光盘等光学盘片就是光保存的应用。

光存储是由光盘表面的介质影响，光盘上有凹凸不平的小坑，光照射到上面有不同的反射，再转化为0、1的数字信号就成了光存储。无论是CD光盘、DVD光盘等光存储介质，采用的存储方式都与软盘、硬盘相同，是以二进制数据的形式来存储信息。而要在这些光盘上面储存数据，需要借助激光把电脑转换后的二进制数据用数据模式刻在扁平、具有反射能力的盘片上。而为了识别数据，光盘上定义激光刻出的小坑就代表二进制的“1”，而空白处则代表二进制的“0”。

Optical storage is the storage of data on an optically readable medium. Data is recorded by making marks in a pattern that can be read back with the aid of light, usually a beam of laser light precisely focused on a spinning disc. An older example, that does not require the use of computers, is microform. There are other means of optically storing data and new methods are in development. Optical storage differs from other data storage techniques that make use of other technologies such as magnetism or semiconductors.