区别：

1、后面接的动词形式不同。be afraid to后接动词原形，即be afraid to do。而be afraid of后接动词ing形式，即be afraid of doing。

例句：He thinks that some workers may be afraid to put questions publicly.

他认为一些工人可能害怕公开提问。

She might not be afraid of implicating her sister. 她可能不怕连累了姐姐。

2、be afraid to后只能接动词原形。而be afraid of后不仅可以接动词ing形式，还可以接名词，也可以什么都不接。例句：

Why should a great community like a university be afraid of nihilism?

为什么像大学这样人才济济的社区要害怕虚无主义呢？

However great the difficulties, there's nothing to be afraid of. 困难再大也没什么可怕的。

3、后面接动词时，两者意思有些出入。be afraid to do表示不敢做某事，而be afraid of doing表示担心出现某种后果。例句：

John was afraid to cross the bridge,for he was afraid of falling into the river.

约翰不敢过桥，因为他担心掉到河里。