(setq line-spacing 10)
这个怎么样？ C-h v line-spacing.
顺便一提：空行是 Org 语法上 分割多个段落的分隔符。如果你不用空行，如下文本在 Org 语法中属于同一段落
只有一个 paragraph:
Additional space to put between lines when displaying a buffer.
The space is measured in pixels, and put below lines on graphic displays,
see ‘display-graphic-p’.
If value is a floating point number, it specifies the spacing relative
to the default frame line height. A value of nil means add no extra space.
两个 paragraphs:
Additional space to put between lines when displaying a buffer.
The space is measured in pixels, and put below lines on graphic displays,
see ‘display-graphic-p’.
If value is a floating point number, it specifies the spacing relative
to the default frame line height. A value of nil means add no extra space.