答案可以在 IEEE浮点数表示法

The answer can be found in the IEEE specification of floating point representation:

对于单一格式，正常数字和次正常数之间的差异在于领先正常数字的有效位（二进制点的左侧位）的位为1，而正常数字的有效位的前导位为0.单格式次正规数称为IEEE标准中的单格式非规格化数754。

换句话说， Double.MIN_NORMAL 您可以表示的最小可能数字，前提是您在二进制点前面有一个（在十进制系统中称为小数点）。虽然 Double.MIN_VALUE 基本上是您可以代表没有此约束的最小数字。

In other words, Double.MIN_NORMAL is the smallest possible number you can represent, provided that you have a 1 in front of the binary point (what is referred to as decimal point in a decimal system). While Double.MIN_VALUE is basically the smallest number you can represent without this constraint.