1. ashamed 意为“感到羞耻的”，形容的主要是主观的感受。如：

I’m ashamed of his behaviour.

It’s nothing to be ashamed of.

He was not ashamed of his lowly origin.

After all, I’ve nothing to be ashamed of.

You should be ashamed of doing that.

I must admit to feeling ashamed of my conduct.

2. shameful 意为“可耻的、丢脸的”，更多的用来描述一种客观上的、基于事实的评价。如：

It was a shameful act.

She’s quite shameful about wearing such sexy clothes.

It was shameful of them to surrender. = It was shameful that they surrendered.